Help with Rotex RO125 problems

[samsmith93]

Hi,

I recently purchased a used RO125 having seen them used extensively for resin projects.

I am building up to making a large table, however in the meantime I have been making some resin serving boards (30x50cm approx) to practice on.

The boards are made, they have been through the planer thicknesser, but now it comes to the sanding, and I am having some issues with my rotex.

Clearly the sanding action of the rotex is very powerful, but the issue i am having is that my pads seem to 'gum up' really quickly. I also am getting noticeable swirl marks, of a much larger grit than the pad i am using (so I am presuming this is from the stuff that is adhering to the pad). I have been starting at about 120 grit and working up to 3000 (120, 200, 320, 400, 600, 800, 1000, 1500, 2000, 3000).

I have watched quite a few videos and 'how to' guides, including the helpful festool live sessions and the Larry Smith stuff. I dont have a festool vaccum its attached to a shop vac (via a cyclone), and I have read a lot about how I need to reduce the suction and so I have this turned all the way down.

I am using it in rotex mode (as that is what the festool people suggested as it has more of a polishing action) and I find that seems to be better than the RO mode.

I am hoping for some guidance and help!!!

The boards I have tried so far are West Red Cedar, but I have some oak boards too - however I have not tried it on them yet as it takes me about 20 minutes to clean all the pads up with a brush after ive used them.

The finish on the wood is acceptable, but the finish on the resin is poor. They were poured over 20 days ago so are fully hardened.

Thanks in advance for any help that anyone is able to give me.

 

[squall_line]

Which paper are you using?

 

[samsmith93]

I am using some of the Deerfos for Festool paper. I have ordered some Platin 2 pads for the higher grits which I plan to use for polishing but they have not arrived yet.

 

[ScotF]

It looks like you are melting some of the finish. Have you tried slowing down the speed?

 

[samsmith93]

It looks like you are melting some of the fish. Have you tried slowing down the speed?

Fish?

In the stuff i had read it talked a lot about using the rotex on full speed and changing the 'aggressiveness' by changing the paper grit. I will try out slowing the machine down tomorrow and see if that makes a difference.

Thanks

 

[Peter_C]

Could try to keep the sander moving more to disapate heat, along with turning dust collection down to lessen the pull towards the surface being sanded.

As to swirl marks, are you cleaning the surface every time you change sanding grits? Once you get swirl marks move back down to a lower grit and remove them. Watch how much pressure you apply.

I switch between Rotex mode, and just orbital as needed, and never leave it in just Rotex mode. Often I only switch to Rotex mode with a final polishing. Of note I have a RO150 which has a larger orbital pattern. Speed is usually turned down some depending.

 

[afish]

I have used many different brands of sandpaper from cheap to expensive.  Hands down the best sandpaper is the 3m cubitron film backed discs.  Its also the most clog resistant I have found.  Try it, it might change your life. 

Do you have any pics of the resin before you start sanding?  What resin are you using? 

Seriously though first step is switching to 3m cube to see if that fixes it.  As far as shop vac vs. dust extractor.  Vacuum is vacuum as long as it isnt getting sucked to tight to the surface this isnt the issue.  You can make a gate valve from PVC to adjust the vacuum if needed.  I use a shop vac. that is plumbed in with 2" pvc and located in a shed for noise reasons.  It works just as good as my ct36ac. 

 

[samsmith93]

I have used many different brands of sandpaper from cheap to expensive.  Hands down the best sandpaper is the 3m cubitron film backed discs.  Its also the most clog resistant I have found.  Try it, it might change your life. 

Do you have any pics of the resin before you start sanding?  What resin are you using? 

Seriously though first step is switching to 3m cube to see if that fixes it.  As far as shop vac vs. dust extractor.  Vacuum is vacuum as long as it isnt getting sucked to tight to the surface this isnt the issue.  You can make a gate valve from PVC to adjust the vacuum if needed.  I use a shop vac. that is plumbed in with 2" pvc and located in a shed for noise reasons.  It works just as good as my ct36ac.

So I just went out and tried doing a face on lower speed at a 1 on the rotex, this seems to have significantly improved the situation on the lower grits. Much less material sitting on the pad after I have sanded.

The problem starts to reappear at the higher grits >1000. I wonder if I simply need to wait for the platin 2 pads and if that will solve the higher grit issues.

If that doesn't work then I will have a look into the 3m cube discs you suggest - although as I can see they only go to 400.

I use a shop vac and have made a valve to allow me to adjust the suction level so I can go from basically nothing to full.

I am using Glasscast 50, it was poured about a month ago so is fully hardened for all intents and purposes.

 

[afish]

Ok, Im not familiar with glasscast but resins do vary in hardness so if its a softer resin it would probably tend to gum up more and yes the cubitron is 400 and under.  Over 400 I use water with a drop of soap in a mist bottle to keep the disc cool and clean. 

 

[Crazyraceguy]

Gumming up comes from a few factors or a combination of them.
The hardness of the material
The grit of the abrasive (courseness)
Swarf removal
Heat, though usually only with plastics

The hardness of the material is a big one. Soft things tear rather than cut. This plays with all of the othe r factors. The more course the paper cuts better, rather than rubbing and making heat, but it needs the swarf removed or that gets reground back into the mess.
Speed also has a effect, especially on heat.

My advice, slow down the sander, start with a lower grit, turn the suction down, but still keep the surface clean. Most of my sanding, that will lead to polishing, is with Solid Surface material and acrylics. The acrylic is far more difficult to do because it is far softer in the first place.

Just realize that "cured" doesn't necessarily mean "hard", certain plastics only get so hard. Maybe looking into different brands or formulas of resins might yield better results? Harder materials "take" polishing better, as in higher shine, and they hold that shine longer too. Softer plastics "wear in" to what ever level of polish that their everyday use demands.

 

[Cheese]

First off I'd start by also slowing down the Rotex.

I've done a couple of slabs with epoxy using a RO 125 and an ETS EC 125. I treat the wood and the plastic as 2 different materials especially in the initial sanding/flattening task when you're using large grits.

The speeds you use on wood will cook the epoxy while the speeds you use on epoxy will take forever to sand the wood.

I start with the RO 125 by working to flatten/blend the epoxy to the same height of the wood, just get it close but work the epoxy first because it's the hardest surface and will need the most machining. Set your speeds & feeds to make the epoxy happy. 

Clean the surfaces, put a clean sanding disc on and then work the wood to blend in to the epoxy...set speeds & feeds to make the wood happy.

Continue this approach and at sometime both the epoxy and the wood will feel evenly leveled and this is the time I bring in the ETS EC 125 to produce a uniform surface across the entire surface. My guess is that this is now in the 320/400 grit range.

Continue on with the sanding but don't dwell too long on the wood areas as they will still erode faster than the plastic areas. Also a mist of water on the plastic areas will produce a nicer finish.

When going to the next higher grit, wipe all of the surfaces especially if you misted the epoxy areas as this swarf will only get reground into the epoxy.

Clean...clean...clean between sanding applications. I usually vacuum first and then wipe with a microfiber towel. If you use the same microfiber towel to wipe successive grit levels, fold it over to make sure the previous grit will not be redeposited on the new wiped surface.

Only for the final polishing do I go back to the Rotex in the geared mode. This is when compounds and polishing materials are used.

Here's an example of the products I used for a walnut countertop...some 6", some 5" and some 4" squares. The form doesn't matter, only the grit does.

And to those naysayers that say they don't need the capabilities of both a 5" & 6" sander, notice the first two discs are 6" while the remaining ones are 5" or less. This was accomplished with an ETS EC 125 fitted with both a 5" and a 6" pad. I'd normally need 2 sanders to accomplish this task.

Final result, American walnut with West System epoxy.

[attachimg=1]

[attachimg=2]

 

[Crazyraceguy]

cheese, what is that router base in that photo? It looks like it could be used for edge guides and or a trammel of some kind, but also Porter Cable bushings too?

 

[Cheese]

cheese, what is that router base in that photo? It looks like it could be used for edge guides and or a trammel of some kind, but also Porter Cable bushings too?

It is an edge guide... [smile]... from Micro Fence, I've since drilled it to be used with both the 1010 & 1400 routers. Currently Micro Fence has a 10% off sale plus free shipping.
https://microfence.com/product/universal-router-plate-kit/

1010 mounting holes are red, 1400 mounting holes are yellow.

[attachimg=1]

Here it is being used on a rail to make shower niches from Kerdi board.

[attachimg=2]

 

[Crazyraceguy]

Oh, ok. Is there some advantage to that, over the original Festool edge guide?
It is nice to sit flat (off the rail), but it does take more width too.

 

[samsmith93]

So I spent this afternoon messing about trying various degrees of suction and various speed settings on the sander.

On Rotex mode the pad just cloggs up, irrespective of the amount of suction that is there.

I tried sanding just my softwood worktop however and it sands that absolutely fine without clogging the pad!!

On my epoxy/wood project however it clogged up really badly.

I tried it on random orbit mode - much less of an issue with the clogging up, however get really bad pigtails and swirls - small bits still seem to be clogging on the pad.

I’m wondering if maybe it is the pads I’m using - I’ll do a post asking if anyone has used the Deerfos ones.

It’s rather frustrating as I went from a cheapo crappy RO sander to this thinking it would be the panacea of sanders! But no joy as yet……

 

[samsmith93]

To add to the previous post the other thing I found confusing is that the boards I am sanding are made of oak, and part of it is cured epoxy resin,

I wondered if it was the resin that was causing the buildup on the sanding pads however
Even when I try and just sand the oak areas avoiding the epoxy I have the same issue.

 

[squall_line]

It’s rather frustrating as I went from a cheapo crappy RO sander to this thinking it would be the panacea of sanders! But no joy as yet……

When it comes to sanding, it's not just the sander, but the abrasive as well.  That doesn't mean "you must use Festool for the sander and the abrasive", but if you were having poor results with a previous sander and all you changed was the hardware, it may be time to look at a different abrasive as well.  Some are more prone to clog than others, and there are plenty of different brands/types that are designed to work better on different surfaces (for example: Festool Rubin is designed for raw wood but not finished wood, Granat is better at working with finished/painted wood).

 

[samsmith93]

In principle I don’t mind buying some granat pads if the consensus is that it’s the pads at fault

 

[afish]

[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. 

 

[Crazyraceguy]

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