Tuesday, 24 October 2017

Bondo On...Bondo Off...

I have a feeling that some of you aren't exactly agreeing with my choices for truing-up the panels that are to be veneered with Bondo, and I get that. I'm a complete novice at this veneering stuff and here I am, right out of the box and I start doing things that are not common processes and I'm using uncommon materials to do it, to boot. I get it. 

So I coated each panel with Bondo and set it off to dry. I was originally going to sand each of them down with 100 grit self-sticking roll paper, stuck to an 18" board, but it turns out the board was too long for the narrow panels and the grit was too light. I ended up using half-sheets of 60 grit wrapped around a specially cut 9 1/2" board. Once the first coat was boarded, I spread a second layer of Bondo over the entire board again, tipping it off to level it, and setting them off to the side to dry completely again.

Twenty-four hours later the Bondo was hard and dry so I went at all the panels again with the board and the 60 grit sandpaper. Working with Bondo is like waxing a car for Mr. Miyagi, the instructor for the Karate Kid. You lay the stuff on one way, and remove the majority of it another. By boarding it, you remove the Bondo completely from only the high spots while the Bondo you leave on the board fills in the low spots. The trick is, always sand at a 45° to the grain, doing so in both directions.

The grain of the board is running from right to left, so sanding
goes from top to bottom, first angled one way,
then angled the opposite way.
The idea is to not only flatten the board so it is ready for veneering, but to lay a "scratch hatch" on it so the Hide Glue has a tooth to grip to. I think the 60 grit leaves a strong enough scratch hatch to work, but if not, I'll let the Hide Glue dry and then sand the board clean again. I'll then hit it with a toothing plane. I think the crosshatching I achieved with the 60 grit paper should be enough, though.

Enlarged, you can see the crosshatching quite well.
As you can see from the second image, there isn't much Bondo left on the panel. Nothing would be gained by leaving a lot of the filler on, but if you do, each panel will have to be worked so their thicknesses are the same.

Now that the panels are fully prepared, I can now get on with sticking some veneer to them. I am planning to use Hide Glue to take advantage of one of its best characteristics - its ability to be turned back into liquid once its been applied. If I can use Hide Glue, if an area of veneer doesn't stick, I can use an iron to reheat the glue and turn it back into a liquid again, then I can work and clamp that specific area without the need to add more glue to it, as heating the glue makes it useable again. If I run into problems getting the Hide Glue to stick to the Bondo, I'll just find another glue to use.

So I'm off to glue some veneer.



No comments:

Post a Comment