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Roundover tearout repair ?

Posted: Tue Oct 01, 2019 11:36 am
by KR500
Yesterday I used my router trim bit on my Simplexx 10 cabinet to clean up the edge joints and then used a 3/8th's inch round-over bit .

All went until the very last round-over on the rear bottom of the back and there is tear out on the top ply splintering off in a big zig zag pattern on the lower rear back from edge up 2 inches .

I'll have to sand the bottom edge roundover in that area to get it even.

I haven't had a lot of experience with wood filler , bond and wondered if any woodworkers could suggest the best way forward .
I also have to fill the small screw holes from the jigs I used in assembly.

Plan B might be a piece of .5 X 3 wood rounded over or chamfered and glued over the damage and attach some wheels for tilt back pulling ?

Re: Roundover tearout repair ?

Posted: Tue Oct 01, 2019 12:46 pm
by Bill Fitzmaurice
I use bondo for repairs. It cures in a half an hour, and is easy to work with. You can spend four times as much for a so called advanced wood filler, but it's just brown bondo.
Not seeing the damage I can't say for sure the best way to fix it, but if it's what I think it is use a flat jig screwed to one side, isolated with wax paper, as a dam to rebuild the corner to its original shape, then round it off again.

Re: Roundover tearout repair ?

Posted: Tue Oct 01, 2019 1:14 pm
by SethRocksYou
I'd use bondo too. Bill mentioned a fairly clean way to take care of it that would minimize sanding. A lot of times you can just slather on more than needed and sand it down flat and profile any contours. In either case, you'll likely have to do a second clean-up round of bondo and fill in little pinholes and such. Don't even stress about it. It's super easy to use and you can do it over and over until you get it just the way you want it. Build it up, knock it down, fil the holes, fixed.

Re: Roundover tearout repair ?

Posted: Tue Oct 01, 2019 2:07 pm
by KR500
Thanks for posting your responses Bill and Seth .
Do you just buy Bondo at an Auto Supply , or is Home Depot a better bet ?
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Re: Roundover tearout repair ?

Posted: Tue Oct 01, 2019 6:14 pm
by SethRocksYou
I usually get mine at the auto parts store or Walmart. Get some plastic spreaders while you're there too. Not essential, but those small shaping rasps knock a lot of bondo off quick and easy. Like this https://smile.amazon.com/Kraft-Tool-DC1 ... B0058I11WU

Re: Roundover tearout repair ?

Posted: Tue Oct 01, 2019 6:42 pm
by CoronaOperator
My cabs are 20 % bondo!, best wood filler ever. I fill tear outs, nail holes, seams, router mistakes, anywhere really. It chemically hardens so you can lay it on as thick as you like and it still hardens in 30 minutes. Here I routed out a hole about 3/8" too big and filled the whole thing with bondo and started over. That patch is 1/2" deep by about 3/8" all around. Worked great.

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Some tips - only mix what you can use in about 5 minutes at a time as it sets up pretty quick. I mix up a batch on some cardboard or a scrap piece of ply, then use a drywall putty knife to spread it around. Make sure you mix it well and have a nice even pink color to it, adding a bit extra hardener is better than not adding enough. Easiest way to sand it is with a random orbital sander with about 120 grit paper. It has some fumes and the dust can't be good for you so have some ventilation and a dust mask for sanding.

Re: Roundover tearout repair ?

Posted: Tue Oct 01, 2019 9:11 pm
by Bill Fitzmaurice
Looking at the picture you want to screw the jig to the cabinet top, then fill the corner and the tear out on the back. The reason you got the tear out is you had the router bit on the wrong edge. If you had the router base on the bottom it should have been on the back, if you had it on the back it should have been on the bottom. My guess is that you had the router base on the back. You're far more likely to get tear out when the bit is going across the grain. When I rout a corner I start slow and watch for tear out. If it does tear I move the router base to the other panel.

Re: Roundover tearout repair ?

Posted: Tue Oct 01, 2019 9:18 pm
by jimbo7
I've had wood splinter like that while cutting auraco with a circular saw.
I find it easier to ease into roundovers on the 1st pass then nice and tight on the 2nd pass. If it's not nice and smooth, I go back around in the opposite direction. Never used bondo, but I will say PL isn't the best option. It tends to have porous air bubbles when smeared over a screw hole then sanded/routed over. I like Durham's water putty.

Re: Roundover tearout repair ?

Posted: Tue Oct 01, 2019 10:06 pm
by Bill Fitzmaurice
If you get splintering like that your blade isn't very good. I use Freud Diablo, 40 tooth in my 6 1/2" cordless. I wouldn't use PL to repair a natural finish cab, but with one finished with Duratex the porosity is a plus for adhesion. I don't care for Durhams, it takes forever to cure and is hard to sand.

Re: Roundover tearout repair ?

Posted: Wed Oct 02, 2019 6:47 am
by LelandCrooks
If you're using duratex for your final coat, when you sand don't sand the bondo past 80g. Prime the bondo with a cheap black primer. I really like rustoleum 2x primer. If the bondo is too smooth, as it sands differently than the ply, it will show through the final finish as different texture. Also over a period of a few years the duratex can flake off the bondo. The primer fixes that and helps with the texture difference.

Re: Roundover tearout repair ?

Posted: Wed Oct 02, 2019 7:06 am
by Bill Fitzmaurice
With a Duratex finish I sand the entire cabinet with 40 or 60 grit discs. The resulting texture gives the Duratex, and primer if you use it, a lot better grip.

Re: Roundover tearout repair ?

Posted: Fri Oct 04, 2019 4:41 pm
by KR500
Thanks everyone , I went to HD today but they were out of regular Bondo, so I'm off to NAPA or Lowe's tomorrow .
Autozone's web site shows most Bondo no longer available so I'm not going to drive there .

Seth, thanks for the tip on the rasp . I still have my father's rasp he gifted me long ago to use .
I had planned on using shellac but with the tear-out bond I might just stain it in something darker.

Re: Roundover tearout repair ?

Posted: Fri Oct 04, 2019 4:51 pm
by Bruce Weldy
I use the bondo in a tube.....I use so little that it's not worth having to mix it up. Cost a little more, but worth it in terms of time and cleanup. Always buy it at AutoZone.

Re: Roundover tearout repair ?

Posted: Mon Oct 07, 2019 3:14 pm
by KR500
I did get the regular Bondo body filler at AutoZone $13 in stock , Home Depot was $8 , .....but out of stock .
AutoZone here also carries the Bondo in a tube , good to know
Thanks for your help everyone , my first experience with Bondo and it worked great