New Sanding Blocks

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PostPosted: Thu Nov 24, 2022 8:28 am
I have a VW Beetle that I'm working on and it will soon be time to strip the old paint, do bodywork and put some fresh shiny stuff on.

I've been using an inline air sander and some speed files, plus a kit of Dura Blocks but they're all straight and a Beetle doesn't have a single flat or straight panel on it (other than the floor, and that's ribbed. So, it's time I organised some decent flexible blocks.

Had a look at the ones that are available commercially and the prices are ridiculous. Seriously, a mid-range kit is over $800!!! A trip to Bunnings (like HF) was called for and I bought some PVC sheet, pipe and glue for less than $50.

Now I do know that the expensive ones are polycarbonate (which is almost unbreakable) and PVC may be a poor substitute but the exercise was also one of proof of concept and some trial and error in how to actually make them. Polycarbonate, even in sheet and tube ain't cheap and I didn't want to be making too many mistakes with it.

First to cut the sheet. Strips 63mm wide to suit 3M adhesive backed sanding paper in a roll. Easy - cut with a handsaw. Then the tube. Easy enough to cut the lengths I wanted but then to cut the slots......

Made a jig. Pretty rough, but it's probably a one use only.
20221124_185014.jpg


... and started cutting the slots
20221124_190011.jpg


Works ok but the blade works by taking out big chunks and a broke a few parts of the tube. Learnt to go slower but ran into strife with one that needed a lot more slots. Had to cut it up and make a couple of small blocks.

Broke out my "precision mitre saw". What a joke - Chinese junk and had to remake part of it before I could use it. Still, even though the cuts were much narrower, it didn't break the plastic and I could control the depth more accurately.
20221124_184858_HDR.jpg


Worked ok but the swarf wasn't all cut off.
20221124_185408_HDR.jpg


Not so bad on the outside but on the other side of the tube it was on the inside.

(cont. next post - 4 picture limit)
Chris

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PostPosted: Thu Nov 24, 2022 8:47 am
So, I had to improvise
20221124_184754.jpg


The socket (about 32mm IIRC) wrapped in sticky back P120 makes a reamer that actually works pretty well, at least for the inside of the tube.

The little piece of Carinya Make-A-Bracket (most useful stuff I've ever come across) has a little cutting edge on the end that slips inside the slot and cleans it up pretty well. Flip it over and use for the outside as well. Took all of about 2 minutes on the bench grinder.
20221124_184803.jpg


So now I have a whole range of them, with slots cut at varying increments.
20221122_165757.jpg


The final one (so far), cut on the mitre box took forever to cut all those slots, but it looks perfect for VW type curves (and lots of other older cars, too).
20221124_195949.jpg


Hardly going to rush out and sell these but they do work, very well, and I'll be giving them a real workout in the coming weeks.

If I was going to make more I'd look at changing the blade in the circular saw for something that won't break plastic and make a jig that hold the piece a bit more securely, including stopping the tube from moving/vibrating. Was a nice change of pace and saved some money as well. Consider it a day well spent.
Chris

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