[HJS]

I wrote in another thread about my DAP plaster of Paris (POP) setting up too fast before I was able to lay in 6 masters. I was trying to make a 2-piece mold. As suggested by others, Durham Water Putty (DWP) had a longer setting time. I did a test of setting times before attempting another 2-piece mold. Testing is my forte. Being a retired scientist who did all sorts of testing like this, so I was in my element... whooo-hoo, back to work again!

I mixed up both so that they poured easily like pancake batter, maybe even a little more pourable than batter, like extra heavy cream. I pored test puddles on a sheet of fairly rigid PVC sheeting.

RESULTS:
POP gott too hard to set in masters in 4 minutes. THAT'S too fast for making a 2-piece mold with 6 masters!!!

DWP had stayed workable for at least 10 minutes, plenty of time to set in several masters.

Also, directions for DWP said that a small slash of vinegar would further delay setting time. So, in a separate patch, I tried adding vinegar. I'm guessing my fluid was about 2+% vinegar and 98% water. This greatly delayed setting time to ~30+ minutes or more. This additional delay in setting time will allow more bubbles to rise to the surface and dissipate.

CONCLUSION: DWP has a significantly longer setting time. If you're new at making 2-piece molds I highly recommend using DWP. Cost is comparable with POP. OK, now I can retire again.

[Troul Hawk]

Thanks for posting you results HJS. I have never used the vinegar and now I know it will work if I ever need to delay my molds much more. I am glad this change will make life easier for ya.

[Spike-A-Pike]

I read a recent post by Vodkaman where adding Elmer's glue to the PoP mix added to the strength of the mold and the ease of removing the pours after they set up. It could get a little spooky around here with a retired scientist (HJS) and an engineer (Vodkaman) with conversations on the exact compound and hydrodynamic of future lures.

Welcome aboard HJS; remember... we only tease the ones we like.

[KcDano]

Since you forte is testing try using a quick setting drywall compound. They make 30-60-90 and 120, which designates the set time. The longer setting time will present more of an opportunity for any air within the mix to migrate out. The removal of air can be facilitated by the use of vibrating table or repeatedly dropping the mold box gently onto the bench or whatever surface you are working on. When the compound sets it will be hard as rock.

[Vodkaman]

Welcome HJS, but don't put your lab coat away just yet, we have a ton of experiments for you to perform.

Good feedback.

[Ed Brabant]

They sell a retarder that plasters use when they need the plaster to stay workable longer. they also have a accelerator to harden it faster. Homless Depot sells it as well as acellerator. I worked with a buddy plastering a few years ago and we used a household product for either retarding or accelerating. i will try and find out what it is and which it was used for. I know it was a spice. I think it is cream of tartar.

[HJS]

Funny this thread came BTT. Yesterday, I just finished yet another 2-piece mold. I'm really in to 2-piece molds now. I'm hooked! Heck, I'm having so much fun that I'm starting to make molds to replace my 1-piece molds. Even worse, I'm starting to make 2-piece molds for lures types I really don't need. (Did I mention its great to be retired!) My last two 2-piece molds were made from Durham Water Putty. DWP has so many advantages that I don't think I'll ever go back to making 2-piece molds out of PoP. Setting time is long enough to set in 5-6 masters with time to spare. Once DWP dries its much harder and more durable that PoP. Maybe PoP is still good enough for 1-piece molds, but for 2-piecers I'm staying with DWP.

Ed - I've heard of delaying additives for PoP but never checked into them. I know with DWP that a splash of vinegar delays setting time. Says so on the box. I use 1/2 tsp vinegar per cup of water. Took 15-20 minutes for the DWP with vinegar to start to firm up.

[Ed Brabant]

What is the price differance. 1 Mold is just not cutting it. I know that plaster is pretty cheap. A 50 pound bag for under $10. It was cream of tartar. Sounds a little crazy but it works.

[HJS]

Ed - Durham Water Puddy (DWP) is a little more expensive than PoP. I bought a 4# container of DWP at my local Ma&Pa hardware store for about $7.50. The same store had PoP for ~$5 for the same sized box. But still, it cost only about 75 cents to make a mold that will last years and make 100s of lures, if not dropped. IMHO, its well worth the slight extra cost per mold. You can make lots of molds from a 4# container. PoP might be good for practice but switch too DWP after you get the hang of it, especially if you get into 2-piece molds. The longer set time is a big bonus when making 2-piece molds. On the other hand, others on TU have suggested mixing in a hefty squirt of Elmers into the PoP and that will make it get harder and more durable.

And I know what you mean by not having enough molds to make for quick pouring, even if just for your own use. The 4" paddletail Bass Assassin is my goto lure for saltwater striper fishing in both the Chesapeake Bay and in the Bath area of Maine. They are great for freshwater too. So now I have enough 2-piece mold capacity to pour 12 paddletails at a time. Thats about a full cup of plastic.

Seems like cream of tartar is a master of many trades, an Elixir of life. Everytime I read a helpful hints article about home remedies to solve a variety of home problems they suggest to use cream of tartar. So now, here on TU, comes another use.

[Pop]

I looked for DWP today and was able to purchase a 4# box for 7.38 +tax. Lowe's had it in stock. Home Depot does not sell Durhams but has DAP water putty. Anyone use the DAP and is it comparable to the Durhams? Pop as in PopPop (Not Plaster of Paris).