kapex and pre-painted wide trim

[dirkgently]

My Kapex is still new to me. I purchased for a number of reasons but, and now finding cutting wider moldings on the flat to be a PITA.
After some research on this site I have found others with similar problems to what I am experiencing with the miters not square (cutting on flat). This has been my first real trim job since purchasing the kapex, and My first sliding saw to boot so I assume some adjustment time is needed.
The trim is all Prepainted (both sides) Maple with the widest pieces for the soffit 3/4"x5.875" wide....hard stuff.

First question....how long should one expect a blade to cut this type of material cleanly before blade dulls? Many of my cuts are now burnt wood when mitered on flat.
When I finish the crown tomorrow I am going to send the blade out to be checked/sharpened......after only 1 medium size kitchen.
I did question if there was a tooth out of alignment (on ownership day 36....) but later decided it was me. The saw checked out square by BTW using the Gary Katz method.

second question....could others share their procedure for cutting wider moldings on the flat? I got so frustrated with my lack of production with the kapex, that I got a new blade for my old single bevel 12" dewalt to cut most of the wide maple soffit boards upright (as I have always done)
Today I gave the Kapex a go again on the flat (after reading info on this site).... and I still struggled with it. I have 1 outside miter which was downright embarrassing.......the long point of the painted cut was ragged and tattered.....I had to quickly grab that white crayon they give with the cabinet touch up kit and fill the gap (note: I am pretty fussy).

Thanks to anyone willing to share

I have ended up knocking off a bunch of hours on this clients bill because I am spending so much time fussing with the saw....What am I doing wrong

 

[peter halle]

First,  [welcome] [welcome] to the FOG.  Sorry to read that you are having issues.

I think that a little more information about what the dimensions and make up (wood) of the trim might be helpful.

We have numerous members here who install cabinets here for a living using the Kapex including someone that I became friends with at a few classes who only installs cabinets for those types of homes that will never allow photos to be taken.

My guess is that we can find you some help.

Peter

 

[live4ever]

I certainly won't pretend to have cut an enormous amount of the material you are working with, but I am surprised to hear of the issues you are having.  So one important piece of information is...what speed setting are you using the saw at?

 

[dirkgently]

Great suggestion on speed. I have tried 5 and 6. I am cutting the 3/4x5.875" (odd dimension) really slow. The dust which does not make it to the midi is usually burnt.
I was told many years ago that painted wood dulls blades....not sure if that is for carbide  blades also.
I recall a job back in 04 (when my dewalt was new) where I had to cut a LOT of wide profile primed poplar crown on the flat.....using a very good blade from woodworking store....blade was dull by the end of a week. I do not normally use hardwoods so I assumed that was normal.
I have been using the clamp for most cuts also.
Should I have purchased a 80 tooth blade for this job?

 

[peter halle]

Honestly I haven't seen the need for the 80 tooth blade.  Mine is still in the package.

With the variable speed - go max - and make sure that the blade is up to full speed before starting to cut.  I went thru an adjustment period when I switched to the Kapex.  Then learn to listen to your saw.  It will "talk " to you.

I am sure that others will chime in with their own ideas.

Hang in there.

Peter

 

[live4ever]

One kitchen seems awfully fast to dull a blade, hard material or not.  Getting a sharp/new blade on the saw will help eliminate that as a variable.  My guess is something else has to be up unless someone gave you a bunch of prepainted ipe. 

Are you only burning when cutting miters on the flat, or also when "regular" crosscutting?  This means you're doing a bevel cut (tilting the saw head), correct?  Are you burning softer materials if you try a bevel?

It's very easy on those 45 degree bevels to inadvertently apply sideways pressure to the sawhead as you're pushing through the cut, even more so if you're new to the whole slider thing.  I was cutting some standard 6" pine base the other day on the flat and definitely felt like I had to take care with how I was moving the sawhead through the cut to not apply downwards pressure.

 

[dirkgently]

Thanks for suggestion. although done with that 6" painted maple I may do some more test cuts on the remaining 4' pc. (kitchen designers called that one pretty close, glad I had no misstates).
There is still some burn on straight (vertical cuts).
My main problem is when saw head is beveled (tilted left or right).....almost every cut is burned.
I did scrape residue off each tooth of the blade today hoping that would help....it did not.
As far as cutting out of square in bevel mode my problem is much like Reno III posted in July 2015. I took a picture today which looks much the same as he posted back then.

 

[KRKWW]

Burning can be caused by excessive pitch build up on the sides of the blade. I have cleaned a blade that was burning and it was "sharp" again. I use a product called Simple Green and spray both sides and set it in a clean oil drain pan for about 10 minutes. I can then usually use a tooth brush or scotch brite to clean it up.

I switched to a Tenryu 80 tooth blade and turned the speed down to 3 and I get smooth shiny ends. Most of my cutting is black walnut and white oak. As a qualifier, I have not had to cut a bevel on the flat as you are yet.

 

[AlexThePalex]

Like above poster said, paint can lead to gunk building up on the blade. Clean it first before resharpening.

 

[dirkgently]

Thanks, I think  you are pointing me in the right direction with the blade cleaning. I scraped "resin" off the teeth as best I could...but it made no difference. I will soak it tonight and see what happens.
I will also try slowing the blade down to see if that helps. never thought a slower than 5 would be good...guess I should try.
I will also check my Dewalt blade to see if there is buildup on it as well. I could be wrong...but seems like the RPM of the dewalt is faster than the 6 setting of the Kapex.

 

[ear3]

Another possible issue -- sometimes there is a small amount of difference in the level of the Kapex bed between the middle portion and the sides (you can test this with a straight edge and feeler gauge).  It's possible as you are cutting the wood one side or another starts to flex/bend in and pinching the blade causing it to start burning the first part of the cut.  This can also happen even without misalignment of the bed if the wood is slightly bowed or twisted.  Have you tried clamping your material as you're cutting it so you minimize movement during the cut?  Obviously your clamping options will be more limited when doing acute bevels, as you can only access one side of the bed.  You can also double check to see what's happening with the saw by two-stepping your cut -- first cut to rough size, then a second cut taking off final 1/4"-1/2" (best for the test if you're still left with a slight offcut rather than just trimming the edge).

As far as the bevel alignment issue goes, as I said in the PM, my fix, unfortunately or fortunately, involved sending the saw in for service. 

 

[AlexThePalex]

I could be wrong...but seems like the RPM of the dewalt is faster than the 6 setting of the Kapex.

Yes, DeWalt 12 inch saws are typically 3600-4000 rpm, while the Kapex with a 10 inch blade has 3400 rpm. This means the teeth of a DeWalt move quite a bit faster.

 

[dirkgently]

Ok, new twist in my research,
I have a grinding sound when I bevel the saw to the left somewhere around 40 degrees it starts. I read a recent post from another who had the same issue.
I assumed the sound was normal.
I sure hope this saw is not like another fine piece of german engineering I purchased.....VW TDI "clean diesel"

 

[dirkgently]

Fantastic Idea about the degreaser for the saw blade!!!
Thank You
I used Castrol super clean degreaser and blade was clean in seconds. I scrubbed lightly with nylon brush and rinsed and dried.
Once on saw It bevel cut (head tilted) much faster, cleaner and only burn mark was due to blade pinch.
Immediately prior to cleaning I cut the same exact piece of 3/4 cdx and it was leaving good amount of burn on the wood and cut was much slower.

cant wait to try on painted maple tomorrow

Hope this thread helps  someone else out there someday......It did not take too much painted wood to gum the blade up badly (blade was new).

The bevel (head tilt) cuts are still not square....a strong 1/32 tilted left and normal 1/32 tilted right.

 

[tiralie]

The trim is all Prepainted (both sides) Maple with the widest pieces for the soffit 3/4"x5.875" wide....hard stuff.

You should be able to cut this nested if you remove the dust collection boot. I just cut some 61/4" crown and I was able to just squeeze it under the blade.

First question....how long should one expect a blade to cut this type of material cleanly before blade dulls? Many of my cuts are now burnt wood when mitered on flat.

You should be able to cut several rooms of crown before you see any real degradation. Maple is a challenge and I have had burning when cutting it but usually because I was moving too slowly.

second question....could others share their procedure for cutting wider moldings on the flat? I got so frustrated with my lack of production with the kapex, that I got a new blade for my old single bevel 12" dewalt to cut most of the wide maple soffit boards upright (as I have always done)

I try to make sure that the board doesn't move on a horizontal plane. I use the clamp the comes with Kapex and sometimes a sacrificial board in front as Gary demonstrates when cutting nested crown. Most of the issues I have had is material sliding slightly into or away from the blade during the cut because of poor support along the length of the board or because it is not sitting flat on the Kapex table.
Tim

 

[dirkgently]

Thanks Tim,
I am not having a problem with my Crown Molding. It is the soffit material which is giving me fits. square edge boards which need to be mitered on outside/inside corners.
I started this thread looking for advice on a procedure to best cut it...I am not blaming the saw....but, I may be changing my tune. This is my first scms....so Initially I assumed it was me.

After cleaning the blade I did some test Bevel cuts first on 3/4" cdx plywood and found it cut better.
Today I got back to jobsite and grabbed the remaining scrap of 3/4" x 5.75" painted maple and was EXTREMly bummed out. Yes it did cut better, but it still burned quite a bit.
I finished up the crown moldings (maple painted) without any trouble...a little burn but I can live with that.

I did some test cuts also today with my 15 yr old dewalt chop saw on a bevel. It has a slightly newer blade than the Kapex......but it is 100 teeth Diablo.
PERFECT cuts on a bevel. No burn. not tear out.

I had switched to the Dewalt for a day during the soffit phase because It was so much quicker to cut the moldings standing upright...and did most of the soffit with that saw. I finished up the last 3 pcs. of soffit with the Kapex and was frustrated all over again with the slow burnt cuts......thats when I started this thread looking for what I was doing wrong.

I really dont know squat about blades (ATB, tripple chip, etc..). I did some research on this site about getting a 80 tooth blade prior to posting........My conclusion was most of the fine professionals here do not use anything other than the 60 tooth blade for finish work......I guess the wood I am working with may be the exception.

I really hate to plop down more money on a 80 or 100 tooth (do they make those) blade for the kapex only to find that it does not help.

I will post pictures later on the burnt cuts from today.
cutting at a slower speed (3 or 4) resulted in MAJOR tearout and a higher speed was better. As someone noted above my Dewalt has a higher RPM rate.....Perhaps faster is better.

I spoke with Festool customer service and am sending saw back for repairs on the grinding issue when I tilt the saw on bevel, and the fact that it will not cut square when in bevel mode.

The saw only has 1 job under its belt.

 

[justinh]

Thanks Tim,
I am not having a problem with my Crown Molding. It is the soffit material which is giving me fits. square edge boards which need to be mitered on outside/inside corners.
I started this thread looking for advice on a procedure to best cut it...I am not blaming the saw....but, I may be changing my tune. This is my first scms....so Initially I assumed it was me.

After cleaning the blade I did some test Bevel cuts first on 3/4" cdx plywood and found it cut better.
Today I got back to jobsite and grabbed the remaining scrap of 3/4" x 5.75" painted maple and was EXTREMly bummed out. Yes it did cut better, but it still burned quite a bit.
I finished up the crown moldings (maple painted) without any trouble...a little burn but I can live with that.

I did some test cuts also today with my 15 yr old dewalt chop saw on a bevel. It has a slightly newer blade than the Kapex......but it is 100 teeth Diablo.
PERFECT cuts on a bevel. No burn. not tear out.

I had switched to the Dewalt for a day during the soffit phase because It was so much quicker to cut the moldings standing upright...and did most of the soffit with that saw. I finished up the last 3 pcs. of soffit with the Kapex and was frustrated all over again with the slow burnt cuts......thats when I started this thread looking for what I was doing wrong.

I really dont know squat about blades (ATB, tripple chip, etc..). I did some research on this site about getting a 80 tooth blade prior to posting........My conclusion was most of the fine professionals here do not use anything other than the 60 tooth blade for finish work......I guess the wood I am working with may be the exception.

I really hate to plop down more money on a 80 or 100 tooth (do they make those) blade for the kapex only to find that it does not help.

I will post pictures later on the burnt cuts from today.
cutting at a slower speed (3 or 4) resulted in MAJOR tearout and a higher speed was better. As someone noted above my Dewalt has a higher RPM rate.....Perhaps faster is better.

I spoke with Festool customer service and am sending saw back for repairs on the grinding issue when I tilt the saw on bevel, and the fact that it will not cut square when in bevel mode.

The saw only has 1 job under its belt.

Aside from the material moving while cutting there are a couple other problems that can cause consistent burning.  Check the saw fences for straight.  If they are toed in towards the blade the pinch as the saw cuts generate friction, heat and a burn.  The saw could be dog tracking ( head/blade not parallel to the rails), or a bad blade.  There's a explanation of how to check for arbor/blade problems and dog tracking in this thread in post 8.http://festoolownersgroup.com/festool-tool-problems/kapex-ks-120-cut-is-warped/ Thin kerf blades in general have lousy tension and they want to flutter even before you add heat to the mix.   

When I cut prefin mouldings I use a minimum of an 80t blade in either a 10" or 12" saw and usually use a 12" saw with a 100t. 60 will do alright in unfinished but not prefin. When I get into mouldings with a tinted finish I often have to switch from a standard ATB to and H-ATB because when the trim is spayed flat they often exceed mil thickness making the finish really prone to chipping.  The higher top grind minimizes it but blades with this grind run hot and dull faster than a normal ATB.  There is a lot more to choosing the right blade for a task than tooth count.

 

[mkasdin]

So does it cut clean at a 90 degree? Flat or standing? It sounds like a combination of things? How about a softer wood like pine, hemlock or fir? I think as another poster mentioned it's either not supported at the end and is pinching on the stock as it is sliding in, while cutting. I'm guessing your maple is clamped down? when you say prefin-ished is it just a base coat of primer or three coats of oil based paint.
I would be curious to see if raw maple did the same thing?

I would probably go with a 80 tooth blade, but would defer with FT tech support before I sprang for a new blade.

Not sure of the thickness of the kerf of the blade, but I would try cutting close to the cut line leaving half the thickness of the kerf as waste. Then coming back on the second swipe and cutting to (on) the line. That way the blade is only cutting half the thickness of the material. It should be a clean cut, no burn marks. You could also do the same and leave a  full kerf 1/16", 1/64 or 1/128" etc., and see if that's still any issue. I don't own a Kapex, but rather a dual compound yellow saw that I stuck a 12" Freud 80 tooth blade on for finish.

Btw, does the blade sound like its cutting clean? You did mention a noise while cutting on a bevel...

 

[dirkgently]

Pictures of cut wood.
1st pic without blue tape is before I cleaned the blade.
The other 2 pics with blue tape show the speed used to cut the wood.

 

[dirkgently]

sorry did not do that quite right. learning curve to everything.