[sdantonio]

I'm looking to make a guitar press for forming laminate top archtop guitar plates. The video referenced below uses steel U-channel which I feel is probably way overkill. But I'm looking for ideas for other ways to do it (also at almost 62 I don't feel like lifting a steel unit up onto and off the workbench when I can probably get away with something much lighter.

https://www.youtube.com/watch?v=7VnOp0a7g0I

The upright members can be replaced with 4x4 fir, the column strength of this stuff calculates out to about 4 tons for a 2 ft column.

My question relates more to the bottom and especially the top cross member which will have to handle the pressure on the bottle jack without rupturing. I'm thinking 2 possibilities:

1. 3 pieces of 4x4 fir glued and screwed together something like the attached pic. (total size will be about 4"high x 12"wide x 28"length nominal, the upright members will be attach inside the "U" cutouts in the ends)

2 a torsion table made with (4) 0.75"x3"x28" pieces of MDF with 0.75 inch MDF skins top and bottom

Thanks,
Steven

[bostosh]

Hi,
do you wish to form and glue up archtops?
Need tooling and forming ideas from aerospace?
This would be no problem in aluminum
then you could bake them hard.
I have the surface data and have made dies similar. to

[sdantonio]

Nice work. I actually don't need anything that fancy. Most if the people doing the work in laminate archtop plates (including Benedetto on some of his models) are using a positive and negative MDF mold set (or similar material). And with my meager output of only a couple instruments a year even cheap MDF would last a lifetime. And with the MDF I can easily change the mold to experiment with different parameters such as arching height.

[bostosh]

You could vacuum bag the thin damp wood easily into female form.
I need to vacuum veneer onto flat aluminum next.
D-18 type acoustic aluminum soundboard.

[bostosh]

notice the cyclodial curve on an archtop
What model are you going for.?

[sdantonio]

I've been kicking the idea of vacuum bagging around in my head, but so far the only move I've made towards it was pulling a compressor out of an old fridge and convert it to a pump. I might give it a shot. It certainly will make the glue dry faster.

I have a topological surface map taken directly from a Benedetto. Not saying that that is the perfect curve, but it's a good start.

I like the curtate cycloid curves too. There was a plugin developed for Rhino something like 10 years ago. It was programmed by a young fellow named Mike (I forget his last name) but it was a project that I suggested to him since he was looking for a good programming project. I don't remember if it was a school project or not. But it worked well for Rhino 3. I don't know if it is still available of was ever upgraded for subsequent Rhino releases. With this plugin if you supplied the outline and the long arch it generated the rest.

[mactec54]

I've been kicking the idea of vacuum bagging around in my head, but so far the only move I've made towards it was pulling a compressor out of an old fridge and convert it to a pump. I might give it a shot. It certainly will make the glue dry faster.

I have a topological surface map taken directly from a Benedetto. Not saying that that is the perfect curve, but it's a good start.

I like the curtate cycloid curves too. There was a plugin developed for Rhino something like 10 years ago. It was programmed by a young fellow named Mike (I forget his last name) but it was a project that I suggested to him since he was looking for a good programming project. I don't remember if it was a school project or not. But it worked well for Rhino 3. I don't know if it is still available of was ever upgraded for subsequent Rhino releases. With this plugin if you supplied the outline and the long arch it generated the rest.

The Press he is using is minimal, his top cross beam is to light, if you look at the bottom that is a little larger than what you would need, but more is better when it comes to a press, the bottom and the top beams need to be the same strength

You could get a press like this from Harbor Freight, a floor standing model, the plate he is lifting on to the top is aluminum so would not be that heavy

This press could be adapted to do what you want, if you went with something like this, make sure you work piece can fit inside the frame, there are many choices for cheap presses

https://www.harborfreight.com/12-ton...ess-33497.html

[sdantonio]

Thanks, I've actually had my eye on that Harbor Freight press too. But I was originally thinking it may be overkill. But now I'm thinking it may be just the thing I need. I also looked at their 6 ton A-frame press, but I don't think it has the capacity for the entire "sandwich" with all the ply and that aluminum sheets (but I'll have to actually run to the store sometime soon because the 6-ton has me confused when the say working height 2-4 inches and capacity 10.5 inches (have to see that one in person to see what that actually means).