So i was pre planning and figure i would run my set up by you guys before i wasted a bunch of time and money. Does this setup look like it will work well? I plan on using a 3m 77 spray to hold the material to the mold walls first. Thoughs? Fyi, Its a fender mold
Of course, why wouldn’t it? What you’ve done there is essentially the intended routing path for MTI; along the entire outside of the part.
I actually only do this on very complex parts where I need to draw the red n in 3/4/5 different directions. Otherwise I often just use the more traditional resin inlet on one side, MTI Hose across the opposing side drawing the resin the shortest distance. Works every time unless the resin needs to flow in other directions.
Yeah I was worried that the resin wouldn’t flow up the walls very well (so 3 directions?). I guess I will give it a go and see what happens. Any thoughts on the best way to calculate how much resin is required?
Well that fender is a very simple shape, you could do it from either side of the part and have the resin flow in one direction. Vertical surface don’t affect flow too much on a part this scale, it needs to be quite large for vertical sides to become an issue.
What I mean by multiple directions is if you were to draw the resin in one direction, then it would likely leave a section dry. Like this part:
It has a tube section on the front, and then the main body has an open bottom (which you can’t see in this photo). So I couldn’t infuse from the left to right, as it would likely leave the front tube section dry. I didn’t want to infuse front to back because that was the longest route. So I ran the MTI Hose around the entire opening on the bottom, then down the front and circling the opening for the tube section on the front. Then the resin inlet was through the middle of the part, so the resin was flowing up the walls and in all directions.
Hope that makes sense, it’s difficult to explain. I’m probably over-complicating things for you anyway, your route will work perfectly! You could also run the MTI Hose down one long side and the spiral hose for the inlet down the opposite side. You wouldn’t have any issues doing it this way.
If you do not have a lot of experience your setup is fine. I would shortn the ends of the spiral about 10 inch. Then you have about the same flow length to the MTI hose from every point of the spiral.
Make sure the bag is 100% tight and your vacuum is perfect.
Yeah i am getting a good vacuum seal during testing but i can only pull 26inHG here at this altitude.
What i am having a problem with though is laying the fabric into the mold. Any thoughts on how to get it down the center and up the sides? Does it need to be 3 pieces?
Ok so i have the part curing and you can see the set up in the attached pic. My gauge told me that we had a small leak somewhere but after an hour we still cannot find it so we went ahead with the infusion. I did see a small area where bubble were forming and form that i think there is actually a leak int he mold body itself. once i pull the part, i will see if i can seal everything up.
The peel ply was a bit of a nightmare… it wouldnt stick to anything! Even with the 3m 77. Also the mesh was really hard to layup the sides and had to be cut in multiple pieces. Thoughts on ways to make this easier?
I tired this stuff instead of the usual blue bagging material but it was really hard to pleat as it was very rigid. Any suggestions on a vacuum bagging material that i should try?
http://compositeenvisions.com/richmond-hs800-nylon-vacuum-bagging-film-60-920.html
thanks!
Hi Man with no name
I do not infuse much now as most of my work is pre preg but i strongly recommend envelope bagging whenever possible, regarding infusion mesh i now only use the product below and you may find something similar over your side of the pond.
Regards Chris
Carbon fibre works LTD
http://www.easycomposites.co.uk/products/vacuum-bagging/easyflow-knitted-infusion-mesh.aspx
Knitted infusion mesh is much much easier to use. But it’s generally quite expensive, so unless I’ve got very complex parts with lots of tight corners, I often prefer to just cut the mesh into pieces, there’s no issue there.
Name is Mo.
I am not quite sure how i would envelope bag this part.
Yeah pre-preg would be the way to go but i don’t have and autoclave… i assume you are using OTA Pre-preg? I would need a controlled oven big enough to use the OTA. ; (
I looked for the knitted infusion mesh here in the US but haven’t found a source.
Yeah since i am only making 4 of the parts for the car, i am not too concerned about cost… just making them functional and pretty :cheesy:
Elite Composites in Aus will ship internationally. Not sure if it is very economical but it’s option.
Surely there’s a source for it in the states though.
On the America’s Cup team I worked for we used 40% shade cloth, specifically http://www.farmtek.com/farm/supplies/cat1;ft_shade_cloth_material;ft_sunblocker_bulk_shade_cloth.html for this use, worked quite well and was nicely conformable
There are some sources in the states. I bought it at Comp1 in the states but also I saw it at several customers there.
But I have also used the sun shade cloth from Lowes and it works perfect.
I always try not to envelope bag, because resin can travel to the backside of the mould what can cause several other problems. I seal at the mould lip and if it is not tight i double bag, and the second bag can be a envelope bag.
Got the part out! Awesome! No pinholes (well some on the side you dont see). I don’t know if the part came out great because of the MTI hose or not but they will get the credit. 3lbs untrimmed.
So from here, suggestions on finishing? Should i clear it or buff/polish it?
Also, with the condition tat it came out in… would the GAC In Mold coating benefit? WHould i get a clear nicer surface. (maybe DDCompound should comment here… i think he is biased! Just kidding)
To help others here was my mold and layup…
Mold
Mdf mold coated with Feather Fill. Sanded and polished
5 coats Partial past wax #2
2 coats Fiberglast FibRelease (wiped on)
Layup
Sprayed 3m 77 between each layer
2 layers of 3k 2x2 twill
2 layers tooling Fiberglass (bi-axial i think) for impact protection
extra fiberglass in mounting location
2 layers 3k 2x2 twill
1 layer of AirTech bleader lease B coated peel ply
1 layer Airtech Greenflow 75 mesh
MTI hose
Standard Spiral wrap
Yellow High tach tape
Richmond HS800 Nylon Vacuum Bagging Film 60
Degassed Max-CLR 1618 Epoxy resin (regulated the flow slowly for the first few minutes then let it flow unregulated)
hopes this helps!
Any thoughts on the best way to finish the part?
What do you mean? Clearcoating? If yes I would fill the pinholes with black putty, wet sand it, wipe it with acetone and then clearcoat.
Nest time use the In Mould Coating, make sure your setup is tight and infuse a perfect part without any pinholes.
But very good work for your first infused part.
Yeah i am not too worried about the pin holes since they are on the backside and there is like 3 of them. I just wasn’t sure if you need to do anything before clear coat. Can you just buff and polish and not clear?
Do you still need to clear after using the IMC?
An IMC is a clear coat, it just comes out mould quality rather than having to do any finishing work, ie. Flatting and respraying etc.
You can just polish the raw carbon part, no issues there unless you need UV protection.