DAP and safety

[hozer]

Hi,

I'm about to build my first ever foam weapons. I have all the materials (I think), and I'm reading the DAP directions, and it says to shut off the gas valve.

I haven't found any practical suggestions on this either here or over the internet, but I would rather not shut off my gas in the middle of winter (and who knows if my furnace would come back on), but I was wondering what "normal" people do with DAP without blowing up their house.

Do you really shut off the gas?
If not, how far away are you from anything with sparks/heat/flames?

Can I DAP in the garage/outside without worrying about it?

Thanks.

[Sir Thurat]

DAP fumes are highly flammable, but you should be fine with proper ventilation. You need to work in an area that is at least 70F, so unless you have a heated garage you're gonna have a bad time. I only worked indoors a couple times when I still had a gas heater, but I didn't turn it off either time, and managed not to blow myself up. But again, I ventilated very well,and took frequent breaks, so YMMV.

[hozer]

Thanks. May I ask what your ventilation setup was?

[Sir Thurat]

Just a fan in the window. I also made sure to cap the DAP when not in use.

[Dangus]

You need to work in an area that is at least 70F

This is not always true. You can work in temperatures as low as 60f, assuming you have low humidity. Source: Six years of Foam Smithing in the Oregon Winter.

[Sir Thurat]

I am unfortunately from IL, so humidity tends to ruin everything =[ In ~80% humidity, any temp under 70 seems to greatly increase drying time or, even worse, make the bonds fail.

[Dangus]

I am unfortunately from IL, so humidity tends to ruin everything =[ In ~80% humidity, any temp under 70 seems to greatly increase drying time or, even worse, make the bonds fail.

Sounds about right. In my experience, humidity (i.e. moisture) is what really kills DAP's adhesive properties. *, at 80% humidity, you must have to wait like 45-60 minutes to get your DAP to even set properly.

[Caleidah]

I am unfortunately from IL, so humidity tends to ruin everything =[ In ~80% humidity, any temp under 70 seems to greatly increase drying time or, even worse, make the bonds fail.

Sounds about right. In my experience, humidity (i.e. moisture) is what really kills DAP's adhesive properties. *, at 80% humidity, you must have to wait like 45-60 minutes to get your DAP to even set properly.

At that point, teh temperature is also generally above 80. Takes ~15 for bonds to start setting up.

[Sir Thurat]

Yeah, on a good day with higher heat it typically only takes 8-15 minutes for the DAP to get tacky.

[seldon]

My experience is you can get it to work in colder weather (although no guarantee on the longevity of the bond) by:

• Keep the DAP can an your materials inside and warm
• Take them out side just moments before gluing
• Spread the glue while it and the surface is still warm
• Put the lid on the can and put it back inside to stay warm
• Stick your stuff together when tacky
• Bring your project back inside between steps so it can warm up (I have a bathroom with fan next to the front door, so I can put it there.)

This allows the project to be messy but not in my house.

[hozer]

I settled on something similar - I do the dapping in the garage and leave the stuff to go tacky inside with a fan and window open.

Except I'm leaving the can in the garage. It's probably 50 in the garage in the afternoon. I should probably leave it in the house overnight.

I might be crazy, but it seems like my foam goes tacky in like 4 minutes and it's completely dry in about 7.

My first sword is awful looking - my foam cutting skills leave much to be desired.

[Dangus]

My experience is you can get it to work in colder weather (although no guarantee on the longevity of the bond) by:

• Keep the DAP can an your materials inside and warm
• Take them out side just moments before gluing
• Spread the glue while it and the surface is still warm
• Put the lid on the can and put it back inside to stay warm
• Stick your stuff together when tacky
• Bring your project back inside between steps so it can warm up (I have a bathroom with fan next to the front door, so I can put it there.)

This allows the project to be messy but not in my house.

I've done this. Seems to work relatively well if you can find the perfect balance between outside just long enough to lose most of the fumes, but not too long as to chill the DAP.

[Kyrian]

My first sword is awful looking - my foam cutting skills leave much to be desired.

Practice and don't be in a rush. If the blade is starting to tear the foam and not cutting cleanly, stop. Making good, clean, straight cuts is critical both for aesthetics and for the quality of the bonds between foam layers. You also might want to consider investing in a 48" metal rule. It allows you to make long, straight cuts without worrying about tearing up the ruler like what happens when cutting with wood or plastic ones.

[Rasheab]

Also you might want to go check out Goodwill (or other thrift store) and spend $1-3 on a knife. You can find some pretty good used knives, and they last a lot longer (understatement) than a razor, especially if you keep it away from cutting glue.

[hozer]

Thanks all. I have done 6 blues now, from 20 to 32 inch cores, all in various stages of overlapping foam layers. Going to do cross guards and counterweights on 5 and 6 today.

What kind of knife? I made the first one with a utility knife, and found it unacceptable. I have found more success with a 6ish inch blade kitchen knife.

It seems like glueing the initial sides is one of my biggest weaknesses - if they're not straight or exactly opposite I end up with problems later.

[Sir Thurat]

A mildly serrated knife (like a kitchen knife) is what Rasheeb was referring to, I believe. The first layer is usually the hardest, I agree.

[Brutus]

Or you can go the other route and get a micro-serrated knife, and that seems to work really well for just about every type of foam. Even ensolite, which can be tough to cut because it is so squishy cuts fairly easy with this type of knife if you move the blade back and forth a lot, and don't use much down-ward pressure.

[Mint]

The key to being successful with utility knives is to constantly ensure your blade is fresh and sharp. If you're using an old, dull blade, you're gonna have a bad time. They come in big ol' 100 packs, so don't be stingy with them if you decide to go that route. Also, as Kyrian said: metal yardstick. Use it. Love it.

I agree that the first layer is the hardest, but it's also the most important one. So take your time and ensure everything is neat and straight before you attach it. It'l get easier with practice, trust me!

Good luck! Sounds like your on a good path to becoming good foamsmith.

[Rasheab]

Thirded. Metal yardstick is one of the best things ever. (I also like a "carpenter's square" or something similar, but your mileage might vary.)

Regarding knife, just a generic semi-long bladed kitchen knife. Presumably straight bladed (I would think serration would rip the foam), but I honestly just went and bought a Goodwill knife and it's been great. The longer blade makes it easier (for me) to keep longer cuts straight (once again, YMMV).

I also love the snap-off utility blade razor/knives though, and use them for a lot of jobs (often in combination with the longer knife).

*protip: if you can find a used Cutco knife, you can cut with it to your hearts content, then make the company resharpen it for you. (other brands might be applicable)

[Dangus]

Thirded. Metal yardstick is one of the best things ever. (I also like a "carpenter's square" or something similar, but your mileage might vary.)

Quilters Square! Pretty much the last word in drawing perfectly straight lines.

One of these, except, 18" long:

[NessiePop]

As far as knives go, I've got an 8" fish filet knife that I've had for 3 years or so. I've made dozens of weapons and shields with it, and it's been the best cutting tool I've used for foamsmithing. Make sure you get one of the little carbide sharpeners and keep it sharp. It's long enough to cut through plank foam easily, and it cuts a long straight cut like nothing else. Worth the cash.

[Haardgrim]

Getting back to DAP and temperature -- are y'all using "DAP" as a generic name, or is there a difference in temperature-dependency between different brands? With the German and Danish similar glues I've tried, temperatures down to around 10C (60F) haven't been an _obvious_ problem, but now I'm concerned that some of my constructions are fragile/unsafe due to glue temperature.

-Hårdgrim Bonebreaker of Monachium

[Dangus]

Getting back to DAP and temperature -- are y'all using "DAP" as a generic name, or is there a difference in temperature-dependency between different brands? With the German and Danish similar glues I've tried, temperatures down to around 10C (60F) haven't been an _obvious_ problem, but now I'm concerned that some of my constructions are fragile/unsafe due to glue temperature.

-Hårdgrim Bonebreaker of Monachium

DAP is a brand name for a substance called "Contact Cement", similar and/or identical types of cement exist under other brand names, yes. As long as you are waiting for both of your contacting surfaces to be dry to the touch you should be fine. If your foam pieces do not want to readily stick to each other, then you need to wait longer. Again, temperature is less of an issue for dap, than humidity is. If I understand correctly the German climate is actually quite a lot like that in Oregon, so I think you're probably fine using DAP at that temperature.

[Caleidah]

Getting back to DAP and temperature -- are y'all using "DAP" as a generic name,

The proper name is 3M DAP Weldwood Contact Cement

[Feydor]

For those of you talking cutting tools, Knives are my tools of the trade, and I've done a fair bit of foam cutting for other things. if your looking for a knife that will last, and will cut clean, Look for a meat carving style knife. They are fairly long, and extremely sharp, with a nice tip perfect to score with before making your cuts.

I also recommend finding a knife with a granton edge, as described here:http://www.webstaurantstore.com/guide/538/knife-guide.html

Using the granton edge means less resistance, which will provide a cleaner cut, and, for those who do large amounts of this) it won't tire your arm out nearly as quickly.

Also, invest in a honing steel: http://www.chefknivestogo.com/sharpening-steels.html.
Use the steel before every use of the blade, making sure to draw the knife along the steel spine first (so that the edge of the blade is the last part to cover the distance). proper honing will increase the life of the edge by 100+%, thus meaning better cuts, and less sharpening.

[Tor]