PDA

View Full Version : Resin casting



Herman
05-04-06, 04:46 AM
In some thread here we discussed resin casting. There I promised to show a picture of my vacuum vessel, which I plan to use to degas the resin, and the silicone.

This is the vessel:
http://www.scalemotorcars.com/forum/images/imported/image_missing.jpg

I has a diameter of approx 8" and a height of 9"

The tube is a glass fibre reinforced epoxy tube, which was lying around at my work. (expensive stuff if you need to buy it. Thick walled PVC pipe could be an alternative)
The bottom and the top were made from a 5/8" piece of glass reinforced epoxy sheet. I made the sheet myself, using a technique which eliminates almost 100% of the airbubbles which are common when producing by hand. (the technique is called "resin infusion" where resin is not applied by hand, but pulled in by vacuum.)

I used a glass of a food jar as a window (to see what is going on in there) and drilled 2 holes, and equiped those with 1/2" threads. One for a vacuum line, one for a ball valve (to break the vacuum once done).

I still need to add the hardware and the seal. The seal will be a self adhesive foamed silicone strip.

Next step is getting the old vacuum pump going again. It has run with the wrong oil, so now does nothing anymore. I hope an oil change will solve the problem...

Edit: before you ask: I happen to work in the composite industry. That's why it is an all composite vessel. Would I be a steel worker, It would probably be steel....

hot ford coupe
05-04-06, 01:42 PM
Beautiful, absolutely beautiful. Thanks Herman for showing us this. I can make that but the pump is going to be another story.

ScaleMotorcars
05-04-06, 02:44 PM
Nice work Herman. Reminds me of when I worked for AB Composites making AT-4 rocket launchers. (no joke) They make a larger version that would have been great for the cylinder part. I wounder if they still toss the defective units in the dumper out back. Thats weapons manufacturers for ya. :D :D :D

Jeff, Keep an eye out on Ebay. Ive sen good older pumps go for under $100.00. Find one in your area and just pick it up to save shipping.

Herman
05-07-06, 05:44 AM
...
Next step is getting the old vacuum pump going again. It has run with the wrong oil, so now does nothing anymore. I hope an oil change will solve the problem...



Did an oil change yesterday, but to no avail. The oil that was coming out looked real bad. I am affraid the vanes of the pump are gone. Looks like it will be either a full overhaul for the pump (material cost: approx $250) or a new pump. (looked at a popular 2nd hand website, but only crappy pumps there). I E-mailed some friend in the vacuum pump business, to see if they have something nice.

Today I will probably put the seals in the barrel, but that is nothing spectacular.

Don Garrett
05-07-06, 06:21 AM
Please keep us posted Herman........I'm finding this to be very informative and interesting.:)

fuzzy
05-07-06, 06:48 PM
Try "surplus center.com", you can get a free catalog and they have a constantly changing stock of new,used equipment.I have used them in the past and they are reliable and prompt.

hot ford coupe
05-08-06, 12:46 AM
Sounds like a winner, fuzzy. Thanks for the help.

Herman
05-08-06, 11:26 AM
Get a pump with a reasonable amount of vacuum. Capacity is not important. We are talking about very small vacuum barrels. Amount of vacuum is what counts. I have no idea of the units you all use, but get a pump with pulls at least 99% of vacuum. I just had the company I work for order a pump which does 99,95% of vacuum.
This at least allows me to make castings at work. Now a cheaper pump for working at home, and I am a happy man again...

fuzzy
05-08-06, 09:42 PM
I built one using a vac pump made by Gast. It's a 220v unit that I see they are advertizing on there website for$85-$90.I haven't tried it out yet. The 12 in dia bell jar I purchased from "Contenti" for about $129 (also online catalog).It's all mounted on a piece of scrap lumber with the platform for the bell jar raised up to overlap the pump to save room.If it pulls a fair to good amount of vac and eliminates a good amount of bubbles I'll be thrilled and consider it a success. All for around $200-$215 and my labor.