Pink Foam Plug ?
#1
Pink Foam Plug ?
Hello, I just spent along time on a nice Canopy / Cockpit Foam Plug for my Hydro and made it to the point of needing to use a filler for coating, to prime and get ready for final sanding and painting. I had the bright Idea of using Bondo Spot potty.
Guess what, It has ACETONE in it. Melted a little hole - Luckily I only did a little area on the Turbine exit top instead of doing a test piece.
Yea,Yea - Stupid me.
Anyway, It is an easy fix- What is the best filler to use to coat the Pink foam that is easily sandable, and will the filler be able to take primer and paint?
Drywall compound??
Appreciate the input, Jeff
Guess what, It has ACETONE in it. Melted a little hole - Luckily I only did a little area on the Turbine exit top instead of doing a test piece.
Yea,Yea - Stupid me.
Anyway, It is an easy fix- What is the best filler to use to coat the Pink foam that is easily sandable, and will the filler be able to take primer and paint?
Drywall compound??
Appreciate the input, Jeff
#2
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RE: Pink Foam Plug ?
You're going to want to put some sort of hard coating over the plug when finished. The best bet is couple of layers of fiberglass and resin. Then you can have a relatively consistent, hard surface to smooth out. Bondo and fillers can be put over this. As far as filling your holes, depending on the size and how much sanding you need to do, you could either use an epoxy mix with filler, or could use something as light as spackle, provided that you are later covering over it with epoxy or similar. The problem with sanding a small patch of epoxy filler in foam is that it's next to impossible to sand it smooth. I'm not sure if you wish to use this part as your final surface or use it as a mold, but odds are that it needs to be rather tough.
Michael
Michael
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RE: Pink Foam Plug ?
I've used drywall compound and it does sand really easy.
What I've done is made the plug from foam then put a light coat of drywall compound on and sand smooth. This takes out any imperfections I had with the plug. Then I put a couple layers of fiberglass over it. DON"T use polyester resin, only epoxy. Then like Michael said you can use bondo and spot putty.
What I've done is made the plug from foam then put a light coat of drywall compound on and sand smooth. This takes out any imperfections I had with the plug. Then I put a couple layers of fiberglass over it. DON"T use polyester resin, only epoxy. Then like Michael said you can use bondo and spot putty.
#4
RE: Pink Foam Plug ?
Update - OK, well I fixed the hole by cutting out the section and adding foam block and reshaping. I have applied compound and sanded three times now the Joint compound. It is a light film over the plug, Still see some Pink showing through / will complete these spots today /
As you have stated, I need fiberglass over the plug to make it hard??
It is pretty hard now, Are you saying I need to have it rock hard to be a good plug, Also, I was told that the plug needed to be the same size as the finished product will be when I pull a form / mold from it. If I add all of these layers of fiberglass sheet to the plug, It will make it to wide in the front, Is it feasible to take 30 min or 1 hour epoxy thinned with ?? and apply it with a brush then sand smooth after curing to give a good surface?
Also, Do you think this shape will pop out of the mold with out making two halves or will it be nesessary to create a split mold. I would really hate to ruin this much work.
Thanks for the help, Jeff
As you have stated, I need fiberglass over the plug to make it hard??
It is pretty hard now, Are you saying I need to have it rock hard to be a good plug, Also, I was told that the plug needed to be the same size as the finished product will be when I pull a form / mold from it. If I add all of these layers of fiberglass sheet to the plug, It will make it to wide in the front, Is it feasible to take 30 min or 1 hour epoxy thinned with ?? and apply it with a brush then sand smooth after curing to give a good surface?
Also, Do you think this shape will pop out of the mold with out making two halves or will it be nesessary to create a split mold. I would really hate to ruin this much work.
Thanks for the help, Jeff
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RE: Pink Foam Plug ?
Yes, you absolutely need a rock hard, glassy smooth surface on your plug. Otherwise you will never get your plug out in one piece and the mold surface will be terrible, requiring many hours of sanding and polishing to obtain a usable mold surface.
You should not need more than 1/32" total thickness of glass over the foam... so you may need to adjust the foam part of the plug to account forr that thickness.
That complex shape will require a two-piece mold, as you're thinking. However, there's no "wasted effort" in what you've done so far. Just make a splitter plate and build the mold 1/2 at a time.
Looks cool!
-David
You should not need more than 1/32" total thickness of glass over the foam... so you may need to adjust the foam part of the plug to account forr that thickness.
That complex shape will require a two-piece mold, as you're thinking. However, there's no "wasted effort" in what you've done so far. Just make a splitter plate and build the mold 1/2 at a time.
Looks cool!
-David
#6
RE: Pink Foam Plug ?
Ok, I have decided to go with the Fiberglass over the plug as you all have suggested. At the times I have used fiberglass, I have found that it does not conform to awkward shapes well at all.
What sizes of fiberglass can I utilize to achieve these forms as in the air intake area and below the air intake. I had a look at Fibreglast.com and was a little confused on the fiberglass mat materials I need, can someone please direct me in the sizes to achieve this goal.
I believe I need something very light and easily bendable for starters for the all three steps. Then progress to heavier as I go.
Covering the Plug:
Glasing the Mold:
Final Project:
I Need to go with an epoxy resin rather than fiberglass resin. Products available? I saw West Systems, pretty expensive but I am sure the best choice.
Thanks for the input.
Jeff
What sizes of fiberglass can I utilize to achieve these forms as in the air intake area and below the air intake. I had a look at Fibreglast.com and was a little confused on the fiberglass mat materials I need, can someone please direct me in the sizes to achieve this goal.
I believe I need something very light and easily bendable for starters for the all three steps. Then progress to heavier as I go.
Covering the Plug:
Glasing the Mold:
Final Project:
I Need to go with an epoxy resin rather than fiberglass resin. Products available? I saw West Systems, pretty expensive but I am sure the best choice.
Thanks for the input.
Jeff
#7
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RE: Pink Foam Plug ?
Use a "satin" or "crowfoot" weave. These types of cloth work very well for conforming to compound curves. An example is here:
http://www.aircraftspruce.com/catalo...120fibergl.php
West systems is a good choice for a resin and there are many others out there. Obviously, regular hobby epoxies are not suitable for this type of layup.
Michael
http://www.aircraftspruce.com/catalo...120fibergl.php
West systems is a good choice for a resin and there are many others out there. Obviously, regular hobby epoxies are not suitable for this type of layup.
Michael
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RE: Pink Foam Plug ?
Use a "satin" or "crowfoot" weave. These types of cloth work very well for conforming to compound curves.
-Tom
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RE: Pink Foam Plug ?
Out at Scaled Composites we used a high solids, filler primer straight over the foam with either a brush or a roller. It takes about 3 or 4 coats. It cures so hard that you can polish it.
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RE: Pink Foam Plug ?
I would finish the plug to the finish you would want. Then dip it in Aluminite casting rubber. Once that has hardened remove your plug and replace the void thats created and poor Aluminite casting resin for a good solid plug that would be easier to work with.
http://www.alumilite.com/
http://www.alumilite.com/
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RE: Pink Foam Plug ?
Judging by the pictures I would suggest some rework of the plug in the area underneath the intake and the intake itself. The picture shows a lip going into the intake. Assuming the split line is a vertical line through the plug the intake lip will lock the plug into the mold and you will not be able to get the plug out without breaking it up. With this mold configuration the molded parts will also be locked in to the mold. The area underneath the intake looks as if it is straight across the plug. This will be difficult to remove from the mold. I would suggest that the surface under the intake be in the form of a vee swept back from the centreline either side of the centreline.
Ideally, when looking at the open mold there should be no reverse angles, cavities, lumps or bumps that will hold the part in the mold. I realize they are unavoidable but even vertical surfaces can be a nuisance.
Ed S
Ideally, when looking at the open mold there should be no reverse angles, cavities, lumps or bumps that will hold the part in the mold. I realize they are unavoidable but even vertical surfaces can be a nuisance.
Ed S
#13
RE: Pink Foam Plug ?
Ed - Through many attempts at making the split mold forms, I am in total agreement about the scoop design. I could not get it on the plug with out trashing it. Too tight of spaces and woukld not go in and around the scoop, So I have rethought my idea and came up with a different design.
I now have a side scoop on both sides. It is narrower at the top and will slip from the mold with ease now. Will take some shots to show you.
Frustruating at times this can be[:@]
I now have a side scoop on both sides. It is narrower at the top and will slip from the mold with ease now. Will take some shots to show you.
Frustruating at times this can be[:@]
#14
RE: Pink Foam Plug ?
Well, here is the redesign. No Locking areas except where the intake inside lip is but will pull back and out..and the plug is thinner at the top then the bottom, Will pull out of the mold much easier and should be ok.
Thanks for the input.
Jeff
Thanks for the input.
Jeff
#16
RE: Pink Foam Plug ?
Well it seems the foam lost it's shape during the curing process. I have not been able to grind the base to the round shape so it looks like I am back to square one.
Had I had used the original cowling I made I think I would have been ok.....I will run it without the cowling until one gets made[:@]
Updates to come later.
Jeff
Had I had used the original cowling I made I think I would have been ok.....I will run it without the cowling until one gets made[:@]
Updates to come later.
Jeff
#18
RE: Pink Foam Plug ?
Well, it seems that by me using two dowels as props to hold it up off of the bench, the weight of the resin and mat made the center of the plug fall a tad and as it cured, the heat may have played a part in it as well., I made the mistake of not having a wood piece on the bottom to conform the curved shape - that would have taken care of the problem. So I will just make another one.
Trial and error, I am learning as I go. I do have a nice mold that is good for nothing now though.
This next one will be a two piece mold and I hope to do it right.
It's a lot of work, and it usually only takes me two times to figure something out and to reassess what I did wrong.
Until then, The boat will run without one.
jeff
Trial and error, I am learning as I go. I do have a nice mold that is good for nothing now though.
This next one will be a two piece mold and I hope to do it right.
It's a lot of work, and it usually only takes me two times to figure something out and to reassess what I did wrong.
Until then, The boat will run without one.
jeff