Help with veneering workflow for continuous full wrap of a speaker

[Barry Blitz]

My speaker is 7" x 10" x 16" with roundover corners. I want only one seam/joint. Cold press method with veneer supplies cold press glue with 12 minute working time. Substrate speaker is mdf. The 1/42 in. unbacked veneer of Karelian Birch Burl will have softener applied.

The top and bottom will be veneered first and cold pressed for at least 90 minutes, then overlap trimmed.

This is now the problem that I have. Do I lay the veneer down on the table and sequentially glue each side of the speaker and rotate the speaker each time I glue another side of the speaker, and then when all sides are veneered then press over each side with the roller? Or is it better to use the roller immediately after each side is applied? In the latter method, I would have to keep the veneer elevated as I rotate the speaker for each side to be glued and veneered. I am concerned with over manipulating the thin veneer that could tear.

I would not glue the final seam area until the end so I can trim the ends.

[Dennis Jarchow]

I have veneered a lot of speakers including curved ones and ones with roundovers. First, is your glue the BetterBond X-Press glue or their Titan contact cement? Since you said cold press that implies the X-Press and then clamping the veneer; but then you mention going over the veneer with a roller which is what you would do with contact cement. Sorry if I am misinterpreting what you are trying to do.

The only way I would attempt gluing veneer to a roundover would be with contact cement or in a vacuum bag and a glue like X-Press or Unibond. A PVA glue like their X-press requires clamping pressure while it cures, and I don't see a good way to do that on a roundover without a vacuum bag (I have done it in a vac bag). Given that you want to do a full wrap, and don't have a vacuum press, contact cement seems like the only way to accomplish that but you can't use contact cement on unbacked raw veneer.

[Paul F Franklin]

I have not used the cold press glue, so can't offer advice on that, but I'll pass along this info in case it's of any use:

Many years ago I manufactured some speakers for a small start-up. After trying a few methods I settled on the heat lock veneer glue. You apply to both surfaces, let it dry and then reactivate it with an iron. It took all the "excitement" out of the process as you could move as slowly as you liked. It especially made the back seam easy as you could avoid adhering both edges until after doing a double cut for perfect alignment. And if you missed a spot and it didn't get fully adhered, it was trivial to fix. It also made the rounded corners easy, which was where I had the most trouble when using other methods that required applying glue to one side at time. Seems I either got too much glue there or missed some spots trying to avoid getting too much glue there.

As an aside, I tried to make one set using elm burl veneer and it was a total failure. Maybe it was the veneer I got, but it was made of many relatively small pieces of burl assembled into a sheet, and even with softener edges were separating at every corner. Most of the units I made, I used paper backed veneer from Certainly wood and it was a dream to apply with the heat lock glue. (the burl was from somewhere else; I have blocked the details from my mind!).

[Dennis Jarchow]

I agree with Paul on iron on being an option for roundovers I have used that too before I got a vac bag. I didn't mention it because the one time I tried it on a raw veneer with a lot of figure, (waterfall bubinga) the veneer developed cracks in some spots on the roundovers.

[Barry Blitz]

Great responses. I do have a vacuum bag, but the roundovers would be too much work for me to create a matching form. And I worry about crushing my box.

The damage to the burl is an issue for me, and am unsure how softened they can be made.

I'll just skip the roundover and keep it square.

[glenn bradley]

Great responses. I do have a vacuum bag, but the roundovers would be too much work for me to create a matching form. And I worry about crushing my box.

The damage to the burl is an issue for me, and am unsure how softened they can be made.

I'll just skip the roundover and keep it square.

It is a wise man who chooses his battles. I am new to veneering and am looking forward to seeing the result.

[Phil Mueller]

Barry, the softener Joe sells works great with burl. It can get you around a pretty small radius. With burl, I’d still use the softener for flat/square corners (as it sounds like your are). Be patient; the softener can take a few days with changing out the paper. I use cauls/clamps instead of running the vacuum for days. Good luck! Look forward to seeing the finished work.

And by the way, from my experience, don’t be tempted to use the PVA/iron method with burl. The expansion/contraction from the moisture in the glue and then heat from the iron can cause the burl to crack, leaving a mess to try to hide, or firewood.

[andrew whicker]

You can buy a bag to stick inside the speaker cab from vacupress to keep it from imploding

[Warren Lake]

Andrew I always blocked up inside so you are saying they make a bag that takes air and fills up to push back? If so how is that done, you fill it first before the outside bag?

[Maurice Mcmurry]

I keep hoping for pictures.

[Kevin Jenness]

Andrew I always blocked up inside so you are saying they make a bag that takes air and fills up to push back? If so how is that done, you fill it first before the outside bag?

There is an "umbilical cord" extending from the outside of the vacuum membrane to the bag in the box, which self-inflates as air is sucked out of the press. I think Darryl Keil of Vacupress covers wrapping a single curved edge with vacuum in one of his videos, but this seems more difficult. Some pictures would help to evaluate the problem.

I'm not sure how it would work for this application in which the veneer has to be wrapped all the way around the speaker cabinet. It seems to me it has to be done by something like hammer veneering, although getting the burl laid down without heat and consequent checking seems difficult. Paperbacked veneer seems like a better bet than rawveneer for this task. I would never use contact cement with raw veneer, but paperback with contact might be possible, or paperback with fsv glue.