[wildwoodbybrianjohns]

Hey man, thats perfect. Thanks so much for this. I think I will make several jigs of different sizes, that can be "standard" in all my boxes.

Have you ever had a problem cutting fabric on the tablesaw, I mean, Im imagining fabric getting caught up in a spinning blade and= disaster!

 

[splintergroup]

Have you ever had a problem cutting fabric on the tablesaw, I mean, Im imagining fabric getting caught up in a spinning blade and= disaster!

- wildwoodbybrianjohns

I would never try to trim off the fabric on a TS unless it was fully glued to the foam. To may things to go wrong =8^0

For trimming the foam, I had added small piece of DS tape in each slot to temporarily hold them securely.
I then placed them in and pushed them into the tape with a wide/thin board along the fold in the foam. The flat surface was leveled out with a thin/sharp Japanese trim saw riding along the slats in the jig. I did the edge trimming the same way.

I found that I could get a better shape at the "heads" of the strips by pushing a length of dowel rod (3/16" or so) into the bottom of the foam folds (secured in place with a few spots of glue to keep from sliding down).

Trimming the fabric on the ends is still a design work in process 8^)

Since the fabric is not attached to the foam (just at the line where the folds contact the backing material), it needs to be wrapped over the ends and secured. Currently I have just scissored a cut along the fabric fold, then folded over the flap and attached it to the end of the foam, repeating for each foam strip. It takes some fiddling to get it looking consistent. This is probably the biggest reason I like the commercial products. With the fabric attached to the foam, cutting on the TS produces a clean edge.

The problem with fully gluing the foam to the fabric is finding the right glue. It has to be able to deform/flex and not bleed through the fabric. I've considered trying the 3M spray and producing the insert one row at a time.
What I'd try first is to wrap the fabric around the top and sides of a single piece of the trimmed-to-size foam. Apply the spray glue, set the fabric over the foam, then place it in a jig slot to dry. Do this for each strip then attach them all together with the backing. The jig would be useful for alignment, but the ribs would need waxing to keep them from being glued to the backing.

Anyway, just rambling here. I'd say give it a try and see what works for your needs. The best thing about the home made inserts is you get to choose the fabric and color.

 

[wildwoodbybrianjohns]

Thanks again, invaluable info.

Re: cutting fabric on the TS, I meant when cutting the whole piece, backer, foam and fabric, after glue-up.

Obviously, cutting the fabric alone is just the dumbest thing ever)

 

[MrWolfe]

Great info here.
Thanks for all the sharing in this thread.
Jon

 

[splintergroup]

Thanks again, invaluable info.

Re: cutting fabric on the TS, I meant when cutting the whole piece, backer, foam and fabric, after glue-up.

Obviously, cutting the fabric alone is just the dumbest thing ever)

- wildwoodbybrianjohns

I grok!

I would only cut the foam/fabric if the entire surface of the fabric was glued to the foam, as is with the commercial inserts. My original creations only have the fabric secured to the foam where the two meet at the junction of the backer board.

 

[CaptainKlutz]

The problem with fully gluing the foam to the fabric is finding the right glue.
- splintergroup

Adhesive are tricky things to find, well sometimes, unless you happen to know someone who worked in the adhesives industry? wink, wink…..

If you want a PERMANENT, non-bleed, flexible, spray fabric adhesive;
3M #24 Foam & Fabric adhesive is a common professional choice for general purpose upholstery applications. Henkel/Loctite/Peramtex makes similar product, but only the more rigid headliner adhesive is sold via retail outlets.

If you want a TEMPORARY, non-bleed, flexible, spray fabric adhesive;
Odif 505 is common choice for upholstery shops, or costume making. There are many many private label temporary spray fabric adhesives sold in fabric shops. Some are even water soluble, and are washed away after assembly. They are very popular as replacement for pins in high volume fabric sewing operations. Often used in 5 gal pail fed pressure pots and special swirl pattern spray guns borrowed from hot melt gun applications. The swirl pattern gun ensures even coverage with thick adhesive that doesn't atomize well.

If you want a PERMANENT, non-bleed, spray adhesive for fabric/foam bonded to solid metal/plastic surfaces; 3M offers headliner adhesive. There is also the Permatex version.

TBH, the headliner adhesives are very close formulations to classic 3M 77 or 3M 90 spray contact cement(s), but are designed to endure higher temperature before degradation, while maintaining better flexibility. As many people eventually find out, Classic contact cement turns hard and brittle after a few months.

The above are easy to find retail suggestions.
Hot melt adhesives are very popular in fabric/foam bonding in high volume production environments. They have zero solvents, low odor, and outside of higher cost application equipment are usually cheapest option when assembling thousands of yards of fabric and/or foam per day. Hot melt adhesives are somewhat selective to type of bonded substrate, but the automotive and sports equipment industries solve this though use of 2-part polyurethane hot melt adhesives. They are too complex for most home shops, so will stop here.
Adhesives are fun stuff to work on, earned half dozen patents while doing it.
Glad you asked. Maybe you aren't? Oh well.

As always with product suggestions, YMMV.

 

[wildwoodbybrianjohns]

So, Captain, I went hunting to day for adhesives, remember we are in Spain now. My first stop was the paint store where I used to buy when I was a painting contractor. This shop supplies painting contractors, and also specializes in the boating industry, so they have much that will make a carpenter happy.

I pick what appears to be the best(most expensive) spray contact cement, am about to pay, and then notice off to the left, both 3M 77 and 3M 74. I chose the 77, and will do some prototyping.

Thanks for your info, rounded out this thread nicely.

 

[John Smith_inFL]

Brian - 3M-77 would be my first choice.
but - I found that if applied too thick, it will (and I mean WILL)
bleed right through the material. so it is imperative that all glued surfaces
are the correct "tackiness" before assembly. (as you said- prototype it first).
looks like your plan is coming together rather nicely !!
I have only two spray adhesives in my box. I find both have their advantages/disadvantages.
the 77 sometimes sprays in globs and the nozzle gums up.
the Loctite 200 sprays an even mist and the nozzle does not gum up.
I know your options are very limited, but, you will be happy with the 3M-77.

.

 

[splintergroup]

Nice information Captain, thanks!

If I find time this month I'm going to dust off my jig and try some new ideas. Getting the ends of the insert rolls "nice" is where I left off and experimenting with full fabric-foam gluing like commercial inserts is where my mind is going.

Any bleeding of the glue through fabric or inflexibility after drying would be a showstopper.

 

[wildwoodbybrianjohns]

Thanks John. I will keep an eye out for that locktite. Lots of locktite variations available here, havent noticed it in a spray, yet….