Clean Seams for Foam?

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#1 AuthoroftheYear on 10 months ago

Every time I go to glue two pieces of foam together (using hot glue), I get a rather unsightly ripple/parting where you can see both original edges of the foam. What should I do?

Also, I don't know if this is more technique or the glue. I've heard that contact cement is pretty good, but also that it can get kind of expensive. What do you recommend?

#2 Penlowe on 10 months ago

Sounds like several factors could be in play:

1. if the temperature of the glue gun is too low, it's allowing the glue to harden too fast and thus it's sitting on top of the foam surface and not allowing the two layers to get as close as possible.

2. If the temperature of the glue gun is too high, it could be heating the foam as you apply the glue and the foam is curling away from the edge.

3. The cuts may not be smooth enough to line up well.

SO, contact cement involves no heat, thus it eliminated two possibilities listed above. It dries slower and therefore requires more patience, but that slow dry allows you to really carefully line up your pieces, reducing issues with the third option above. It's not expensive, costs the same as Mod Podge to use the ordinary brush on type, but does require a ventilated work space. Read the instructions! It's an unusual process, but it works really well.

Yes, you can get spray type contact cement (Super 77 and other brand names) I do NOT recommend it for this use. The spray type is for large areas where having over-spray isn't a problem. When building you really need concentrated, careful application, which simply isn't an option with sprays. And they cost a lot more than the brush on type.

#3 Dictamnus Albus on 10 months ago


honestly contact cement "price hike" comes from using commercial grade brands

a jar of DAP brand (walmart, home depot, lowes), will run about the same price as epoxy glues, gorilla x or titebond 1 wood glue (8oz) which is all around 8-10$
but remember, you get alot of uses out of glue, so the dozens of smaller things or few large things you can make, the value is spot on

personally ive never had any issues with the fumes (from most products not just glue)
and my workspace dosnt have the greatest airflow,
just dont huff it or get super close to your face, barring any sensitivities,

(the biggest offender is super glue, the fumes are potent, and highly irritate mucuos membranes (ie eyes, nose, throat)

you should be fine, however if you plan to be spending alot of time with such products,
then yes, get a mask (with activated carbon filter, is minimum effective protection,
its equal to a dryer sheet in construction)

or respirator (VOC filter, volitile organic compound (might also be a carbon filter but is more substantial)

if your foam dosnt have super clean edges, sharpen your blade,
get a cheap hardware shop whetstone, dont waste money on those garbage cheap shaprening dohickys,
a cheap whetstone or honing rod is far more superior
not that replacing utility or snap-blades is particularly costly,
but you can save a few bucks, and sometimes even fresh blades dont leave super clean edges
1-2mins on a stone can get you a shaper than new egde, even on a blade youve been scraping against a sidewalk (less time with practice, and less damaged blades)