Got an RTV mold made...

[jdowney]

Next comes the urethane for casting the palm shelf. I think I'm supposed to wait 3 days for the silicone mold to finish curing, not sure I can wait. I'm a bit worried about the 3 minute gel time. Yikes is that ever fast! If it works well, I'm thinking of making up an extendo-butt pad too. I'd like another 1/2" to 1" LOP personally, or I'd like the sight further forward.

I'd post pics, but my wife went to visit her sister and took the camera with her. Next mold will be prettier anyway :icon_biggrin:

[The Great 308]

That sounds great! I am excited to see what the finished grips look like. I will be getting my rifles back from IGF in about a week and I am excited to see what the PSG1 grip will look like on my MSG90 clone. IM me when you get them done and I will send out payment for my three grips.

[11C ABN]

I'm especially happy to see this come to fruition. I'm thinking that while it may have not been discussed much.

I for one would love to see a CETME DMR and/or Sniper Version.

I'm hoping that some one on this board could manipulate and/or fabricate an American dual stage trigger and/or G3SG-1 and/or Timmy type trigger for this rifle system

One of the reasons is that HK is suing all the clone makers. I have yet to see CETME Spain sue HK.

[jdowney]

Got a palm shelf cast.... but its full of bubbles. I wasn't sure if the urethane resin would melt plastic cups, so I used a couple old jam jars for measuring and mixing. That was the mistake, even a tiny amount of water causes the resin to "boil" once it heats up. So next one will be better...:icon_biggrin:

Resin is also harder than I'd thought, more like a soft polystyrene than what I associate with urethane. I can get some softer urethane from another vendor - the guy I've been dealing with says he only carries the softer stuff in 5 gallon quantities (waaaaay more than I can use!), mostly because its very tricky to measure and the harder resins are more forgiving.

So stay tuned, this is a lot of fun if nothing else!

Good thing the wife's away this week, not sure she'd like my little chemistry lab set up in her kitchen :eek::icon_biggrin:

Oh yeah, Great308, still got your two standards, I'll PM you when I've got this down (thanks!)

[bladeworks123]

If you can't get the bubble issue to work out, you might think about building yourself a small vaccuum chamber to either use on your urethane mix before pouring or putting your mold in after pouring while it sets. I do that on hidden tang knife blades in antler to make certain that I get good adhesion. It will definitely pull the bubbles out.

[jdowney]

In this case the bubbles were caused by water in the resin, and when the resin hits 200+ degrees, the water turns to vapor and makes the whole mess look like its boiling. Turns out it hardly takes any water to get that problem, just a little fog in a capped jar. Switching to disposable cups now, though I couldn't get paper in this little town.

I may yet build a vacuum chamber, it would be useful for making the rtv mold as that stuff is a lot thicker and does tend to hold bubbles from mixing. What do you use for a vacuum source?

[WildBillCody]

Freeman supply is where I got my stuff from, shipping hazmat is expensive.
You can use a refrigerator pump as a vacuum pump.

[GearShanty]

Be careful of the large containers of the 2-part plastics. Most them are only stable for about a year once they are opened.

[jdowney]

Be careful of the large containers of the 2-part plastics. Most them are only stable for about a year once they are opened.

Thanks for the heads up :thumbup:, I've been figuring six months, but as dry as it is out here I've probably got longer. I've been told that's a good reason not to buy from outfits like McMaster Carr that don't specialize - their product is older.

Thats part of the problem with this stuff, you don't want to pay hazmat shipping twice, but you can't necessarily use up a larger quantity.

[jdowney]

I've now got 7 usable palm shelves. This resin is a soft plastic, but not a hard rubber. If it were thin, like less than 1/4" it would be fairly flexible. The down side to these is that they're going to be a little more difficult to fasten to the wood and stay adjustable, but the up side is that I can texture them and they will provide rigid support for the hand. Once I get a complete grip built, I'll get some pics up and take an informal poll as to shelf materials.

[turbothis]

sounds interesting....pics?

[jdowney]

sounds interesting....pics?

Coming next week, wife's still on vacation with my camera :icon_biggrin:

[jdowney]

Ok, here we go with a pic.
<a href="http://s699.photobucket.com/albums/vv353/k31shooter/?action=view&current=dscn2210.jpg" target="_blank"><img src="http://i699.photobucket.com/albums/vv353/k31shooter/dscn2210.jpg" border="0" alt="palm shelves"></a>

still have to clean up the seams, may try making a 3 part mold next time to keep the seams at the edges. Depends on if I need to make softer rubber ones too.

Just for fun, here's another on going project:
<a href="http://s699.photobucket.com/albums/vv353/k31shooter/?action=view&current=dscn2218.jpg" target="_blank"><img src="http://i699.photobucket.com/albums/vv353/k31shooter/dscn2218.jpg" border="0" alt="Scopes"></a>
A whole big box or two of Weavers that either need cleaning, lens gluing, or something else entirely. There's even a couple with the reticles at 45 degrees to the adjustment! They all belong to a friend of mine in Las Cruces.

[tar&f]

looks great , can't wait to see the finished product