Help with Rotex RO125 problems

[afish]

I too was curious if his troubles are isolated to a certain grit range.  1st step is good paper though regardless.  Granat is my 2nd pic. Not sure how much or the condition of the resin hes starting with and how much he needs to remove.  I grain fill with epoxy but apply very thin coats with a squeegee, so there isnt a ton of sanding.  However doing a pour is different and I would assume he has more to flatten.  However by the time he reaches 220 to 400 and above there shouldnt be enough sanding to cause excessive heat.  I would follow these basic rules for success:

1. Start with good quality sandpaper no matter what grit you are using
2. NO rotex mode for "sanding finishes" rotex only once you reach the polish stage and are using a foam or lambs skin type pad after you have sanded through 1500 or higher
3. slow the sander speed like 2 or 3
4. no pressure especially in the higher grits just guide the sander
5. adjust suction as low as possible to still get good dust but not pull sander down (that's the same as pressing down on sander)
6. work up through the grits with no large jumps between grits
7. 400 and higher you can use a light mist of water with a tiny bit of soap I use about 1/2-1 drop of dawn per 32oz. of water it will work wonders (make sure your sanding sheet is wet approved) film back.  You are not flooding the surface like wet sanding a car. Frequent light mist when your slurry starts becoming more like sludge.  wipe with micro fiber and re mist as needed
8. clean between grits ( I blow with air first to remove 98% off part and bench then wipe with damp not wet micro fiber
9.  If you need to remove a lot of material at the start use some type of cutter like a router with a fly type cutter and sled, card scraper etc. 
10. Soft pad seems to help too.  Once I reach the higher grits I use a super soft foam interface pad on a pneumatic sander for "wet type" sanding. 
11. Remember High Gloss finishes are tough and it takes time thats why its expensive. 
12. Always Keep sander moving

 

[samsmith93]

What grit are we talking here? Also, what is the goal at this point? Are you leveling, smoothing, polishing?

So I’ve got boards which have been through the planer thicknesser. I’m trying to smooth them over and then particularly when it comes to the epoxy areas get them polished to a good shine so they are glossy.

I’ve been starting at 120 grit then working up to 3000
120,240,320,400,600,800,1000,1500,2000,3000

I had read that platin 2 was a better option for the higher grits (1000,2000,4000) but that hasn’t arrived yet.
Mainly the swirling issues appear at the higher grits >600. The photo I’ve attached is of a 1000 grit pad I believe after about 20 seconds of use.

I’d brushed and wiped the workpiece and brushed the pad to make sure it was completely clean before use, the small specs that have built up are what I believe to be responsible for the swirls!!!

 

[samsmith93]

[doh] There is no magic wand.  Cheap paper sucks.  To spend 600 on a sander then slap some bargain bin paper on there is one step forward 3 steps back.  spend the 8 bucks and try the 3m here If you like it you can get more grits.  If not your out 8 bucks.  Sorry, last time I will  [dead horse]
and NO rotex mode till you move to polishing stage.

I can’t seem to find them 3M pads in a multipack as readily available in the UK. I can get hold of a sample pack of granat for about £25 which I’m happy to try!

I really welcome as much criticism as people are prepared to give me! Clearly I’m doing something wrong so I’m happy to learn!

 

[samsmith93]

I too was curious if his troubles are isolated to a certain grit range.  1st step is good paper though regardless.  Granat is my 2nd pic. Not sure how much or the condition of the resin hes starting with and how much he needs to remove.  I grain fill with epoxy but apply very thin coats with a squeegee, so there isnt a ton of sanding.  However doing a pour is different and I would assume he has more to flatten.  However by the time he reaches 220 to 400 and above there shouldnt be enough sanding to cause excessive heat.  I would follow these basic rules for success:

1. Start with good quality sandpaper no matter what grit you are using
2. NO rotex mode for "sanding finishes" rotex only once you reach the polish stage and are using a foam or lambs skin type pad after you have sanded through 1500 or higher
3. slow the sander speed like 2 or 3
4. no pressure especially in the higher grits just guide the sander
5. adjust suction as low as possible to still get good dust but not pull sander down (that's the same as pressing down on sander)
6. work up through the grits with no large jumps between grits
7. 400 and higher you can use a light mist of water with a tiny bit of soap I use about 1/2-1 drop of dawn per 32oz. of water it will work wonders (make sure your sanding sheet is wet approved) film back.  You are not flooding the surface like wet sanding a car. Frequent light mist when your slurry starts becoming more like sludge.  wipe with micro fiber and re mist as needed
8. clean between grits ( I blow with air first to remove 98% off part and bench then wipe with damp not wet micro fiber
9.  If you need to remove a lot of material at the start use some type of cutter like a router with a fly type cutter and sled, card scraper etc. 
10. Soft pad seems to help too.  Once I reach the higher grits I use a super soft foam interface pad on a pneumatic sander for "wet type" sanding. 
11. Remember High Gloss finishes are tough and it takes time thats why its expensive. 
12. Always Keep sander moving

Thanks for such a comprehensive response,

So my boards have been sanded so many times in various ways now they are very flat! Basically I’m just trying to get the small swirls out of them and leave them with a glossy finish. The oak comes up beautifully but it is much more forgiving of the marks than the resin area. The marks that are left are too big to polish out.

R.e 1 - I’ve been using ‘deerfos’ paper, haven’t found much in the way of reviews, I’m going to try some granat as clearly people have good experiences with that. I also have some Platin 2 coming for the higher grits - I wonder if the softer ‘foam’ type pad will help with swirls at the higher grit ranges.

R.e 2 - I’ve watched so many videos about rotex v RO mode - some people say use rotex the whole time, some people have said use initially then at the end for polishing. I seem to get much worse swirls with the RO mode when I get to 600 grit and above.

R.e 3 - I started off using it at a 4 or 5, then someone suggested this may be causing too much heat, and I read about how I should adjust the aggressiveness of what I’m doing by changing the pad, not the speed, so I’ve been using it on 1 since then.

R.e 5 - I’ve got it attached to a shop extractor, I don’t own a CTS. Its adjustable however from basically zero to very high, and I’ve messed around a lot with the degree of suction, it almost seems to depend on the grit range as to how much suction is needed.

R.e 7 - I did briefly try wetting it as someone suggested that, I didn’t use a mister though, I’ll get one and try it. I did have even worse buildup with that though, it caused a thicker paste like buildup on the pad.

R.e 8 - I’ve been wiping the piece in between each grit, I’ve also been cleaning the pads each time before I use them. The buildup on the pad is so solid, I can’t air blow it off I have to brush it with a stiff toothbrush basically.

R.e 9 - Before I’ve started sanding the boards have been through a planer thicknesser so they are flat, I’m just sanding out the marks from the planer and then smoothing over.

Thanks again for a helpful reply, I’m wondering with your last few suggestions whether I should stop sanding at about 800 grit and change over to polishing with a compound of some sort.

 

[afish]

If you cant get the 3m in the UK get the granat.  I havent used platin but Im assuming its similar to 3ms trizact which is another good product designed for clear coat.  once you reach those higher grits it really shouldnt be taking much to sand out.  If your making paste then you are sanding to much between spritzing and wiping 1-2 passes then wipe.  I think you will need to go up to 1500+ before trying to compound.  Anything less than that and its not going to polish well.  I typically use Meguiers 101 and 201 because its easy to get around me and works well and isnt overly expensive.  I dont have the bottle in front of me but Im pretty sure the 101 (heavy cut) says it will remove up to 1200 grit scratches.  In my experience thats even optimistic.  I like to go to around 3000 then break out the polish. 

 

[samsmith93]

If you cant get the 3m in the UK get the granat.  I havent used platin but Im assuming its similar to 3ms trizact which is another good product designed for clear coat.  once you reach those higher grits it really shouldnt be taking much to sand out.  If your making paste then you are sanding to much between spritzing and wiping 1-2 passes then wipe.  I think you will need to go up to 1500+ before trying to compound.  Anything less than that and its not going to polish well.  I typically use Meguiers 101 and 201 because its easy to get around me and works well and isnt overly expensive.  I dont have the bottle in front of me but Im pretty sure the 101 (heavy cut) says it will remove up to 1200 grit scratches.  In my experience thats even optimistic.  I like to go to around 3000 then break out the polish.

I’ve got some megs 101 and 201 which I’ve used on the car with a DA before so I can give them a go on it, just gotta get to the 1500 grit ish state without these bloody swirls

 

[afish]

I dont do the thick epoxy pours or live edge slab work like IM assuming you are doing.  Dont those who do top coat the epoxy too.  Epoxy doesnt like UV so I would think you would be topcoating with some type of urethane for protection and polishing.  I know epoxy polishes but if you are having issues with the resin then maybe just sand it to 400 and lay down some 2k clear. then polish that

 

[samsmith93]

So - I got hold of a sample pack of the Granat pads from ebay (https://www.ebay.co.uk/itm/192886095956) and gave them a go.

For the most part, the dust situation is improved versus the deerfos cheaper pads I was using.

The problem still however seems to be at about the 600-1000 grit range I get some build up on the pads, and I believe this is what is leaving these swirl marks appearing in the work, which are much deeper than their respective grits, and therefore don't sand out with the higher grits - so when I get on to the polishing phase they are still visible. (If I go down a grit to sand them out then I still end up with the same issue as I get to the 600-1000 stage as I go up again).

The Megs 105 and 205 'apparently' can remove 1200 grit scratches - but i'd say the marks i get are in something around the 400-600 grit area so obviously they don't come out.

The results I am getting are certainly a huge improvement from what I had when I started asking for advice on this. 

I welcome any other suggestions and thoughts that might help guide me to the solution!

 

[Lbob131]

Below is an overview of common grit numbers and their recommended applications:

P40-P60: For stripping finishes and paints, smoothing rough pieces of lumber, removing stock from thicker pieces of metal, or removing knots or bumps in wood pieces.
P80: This is the recommended starting grit for working with hardwoods. It also does an effective job of removing shallow scratches from metal surfaces.
P120: Recommended starting grit for softwood sanding.

P180: Smoothing surface irregularities and raised wood grains.
P220: Appropriate for wood stain preparation or commencing surface finishing.
P320: Wet sanding or sanding between coats. (Be sure to use an abrasive that’s compatible with wet applications.)
P400: This grit does a good job of preparing a surface for finishing oils or smoothing top coats. It is also used as a finishing grit for many materials.

P600 and up: Any grit above the 600 range is recommended for plastics and metals, fine wet sanding, or preparing a surface for polishing. Abrasives scratch metal far easier than they scratch wood. Scratch marks also aren’t as easy to remove from metal as they are from wood. Therefore, fine to ultra-fine grits from 600 to 1,200 are most useful when polishing metal.

 

[Lbob131]

The problem still however seems to be at about the 600-1000 grit range

I  didn't  think  600-1000  would  leave  swirl  marks.
Perhaps  the  600-1000  is  just  highlighting  the swirl  marks  from  previous  coarser  grits?

I have  the Rotex 150  and  90.

 

[afish]

the finer paper tends to clog easier when dry.  Some finishes are more prone than others so I imagine epoxy is the same.  Here is a video that highlights the damp sanding I mentioned.  the key is slurry not sludge.  frequent wipes and minimal water.  You are just creating a small lubricant to keep the paper from clogging. 

 

[samsmith93]

The problem still however seems to be at about the 600-1000 grit range

I  didn't  think  600-1000  would  leave  swirl  marks.
Perhaps  the  600-1000  is  just  highlighting  the swirl  marks  from  previous  coarser  grits?

I have  the Rotex 150  and  90.

This is why i think it is the build up on the pads that is the issue - i meant to get a picture todya but didnt get round to it - ill try to tomorrow.

 

[samsmith93]

the finer paper tends to clog easier when dry.  Some finishes are more prone than others so I imagine epoxy is the same.  Here is a video that highlights the damp sanding I mentioned.  the key is slurry not sludge.  frequent wipes and minimal water.  You are just creating a small lubricant to keep the paper from clogging. 

Ok i will give this a go next - is there anything i should be aware of when wet sanding wood and epoxy together.

Also:
1. Is it ok to wet sand with Granat
2. How am i best to clean the pads after sanding

Thanks

 

[afish]

Im assuming the wood was coated in the epoxy so it should be reasonably sealed unless you planed a lot off.  This is partly why I suggested sanding up to 400 and clear coating with some 2x urethane which will seal and protect both from UV.  The epoxy will yellow more if exposed to UV.  The 2x urethane will also polish good.  I dont do any deep pours like what you are trying to do but I do, do some high gloss work.  Im assuming it should be pretty much the same. 

I dont believe granat is rated for wet.  You can buy some 5 and 6 wet/dry discs off Amazon.  Im also assuming the platin might be able to be used wet. 

As far as tips dont go crazy with the water.  The video shows it well.  As soon as the slurry starts to thicken, wipe and mist again if needed.  A very small amount of dawn will help the water.  Im talking like no bigger than a pea size drop per 32oz. of water.  I use the Zep spray bottles from HD. To clean the pad I spray the pad down with the same mister bottle and dab on a micro fiber.  If you are doing it right there should be very little on the pad.       

 

[samsmith93]

Im assuming the wood was coated in the epoxy so it should be reasonably sealed unless you planed a lot off.  This is partly why I suggested sanding up to 400 and clear coating with some 2x urethane which will seal and protect both from UV.  The epoxy will yellow more if exposed to UV.  The 2x urethane will also polish good.  I dont do any deep pours like what you are trying to do but I do, do some high gloss work.  Im assuming it should be pretty much the same. 

I dont believe granat is rated for wet.  You can buy some 5 and 6 wet/dry discs off Amazon.  Im also assuming the platin might be able to be used wet. 

As far as tips dont go crazy with the water.  The video shows it well.  As soon as the slurry starts to thicken, wipe and mist again if needed.  A very small amount of dawn will help the water.  Im talking like no bigger than a pea size drop per 32oz. of water.  I use the Zep spray bottles from HD. To clean the pad I spray the pad down with the same mister bottle and dab on a micro fiber.  If you are doing it right there should be very little on the pad.     

The piece is 50% wood 50% epoxy, similar to this -

&s=f4ee2b613c74861ad01740335edcc255bf77891d

Would that be ok for wet?

 

[afish]

Its hard to say there are some factors to consider as I mentioned earlier.  This is a little outside of my normal work.  I am using epoxy to grain fill then spraying with 2x clear.  Then wet sanding and polishing that if a really high gloss finish is desired.  However at that point the wood is very well protected by epoxy and multiple layers of clear so I have no issues with water.  The wood should have absorbed some of the epoxy offering protection from the water. however if you plane or sand to far you will be removing the epoxy and exposing some raw wood.  you could always make and try a sample board. But 

Im also not sure on what the final results are that your looking for.  Are you wanting a super high gloss finish that looks like a show car or something with some shine but gives a more realistic look. If you want the super high gloss its most likely going to involve doing the epoxy pour, plane/flatten, sand, more very thin layer/ layers of epoxy to grain fill any exposed wood, sand again, spray clear coat, wet sand, then polish.  This is going to give you the highest gloss and smoothest finish like a show car.  It starts to look a little fake to me sometimes but to each their own. If you want something a little less glossy that still looks like real wood there are some other methods that some of these epoxy makers use involving Osmo.  Most dont require sanding into the higher grit range.  Heres a couple videos of the Osmo technique. First video shows 4000 grit vs. 320 grit and the second the guy only goes as high as 600 after applying the Osmo I think he sanded to 320 or 400 before coating with Osmo.  Personally I like the look of the Osmo where there is still some grain.



I did