One of the projects is to make a fiberglass boat from a Laois mold, I have now shaped and drilled the hole then covered the hull with a mixture of clay and mold sand and now I am almost working with a sea boat I want someone to walk me through the steps I have followed some articles and YouTube videos then the next steps are to put in the epoxy mix, then put in the separating wax, PVC. Then apply the gel, then apply the fiberglass, ice resin, or regular epoxy, then sand it. I want some details, guys, I want some details, for example, is it possible to apply the epoxy layer and then apply the wax without it seeping in or being absorbed by the texture of the sand, clay, and plaster, as well as some preparation or links to the exact quantities of each component when applying on a website? Is there a mistake in the order?
The Boat Design & Boatbuilding Site
Building a clay mold and extracting a fiberglass boat
- Thread starter Abcie
- Start date
gonzo
Senior Member
- Joined
- Aug 28, 2002
- Messages
- 18,442
- Reaction score
- 2,451
- Location
- Milwaukee, WI
That mold looks really rough. You won't be able to wax mold sand at all. Probably the best solution is to paint the mold first. However, you would have to be very careful when laminating to keep the mold from breaking. Polyester resin is much cheaper than epoxy and easier to use too.
This sounds like a really bad plan!
Is this process proven?
Are your local boats shaped and then built like this, or is it your design?
If you’re set on using this process of molding, wouldn’t it be easier to use a male mold?
Is this process proven?
Are your local boats shaped and then built like this, or is it your design?
If you’re set on using this process of molding, wouldn’t it be easier to use a male mold?
seasquirt
Senior Member
- Joined
- Dec 29, 2015
- Messages
- 384
- Reaction score
- 200
- Location
- South Australia
If it was me, I think I'd line that duck pond with foam as closely to shape as possible, glued well with solid internal bracing, extract the shape in one piece, then fair the foam plug, making it much shapelier, and then glass it when acceptable, and go from there, with a much better shape.
Or get some steel mesh and concrete, and make a ferro-cement hull in the hole, just for laughs, then dig it out.
It is an odd shape hull bottom. With no size or scale, except for the hammer, it looks to be about 10 feet long. That's a lot of expensive resin and glass to waste unless you have a market. Good luck with your project; don't spend too much time and money, and you could get a real boat.
Or get some steel mesh and concrete, and make a ferro-cement hull in the hole, just for laughs, then dig it out.
It is an odd shape hull bottom. With no size or scale, except for the hammer, it looks to be about 10 feet long. That's a lot of expensive resin and glass to waste unless you have a market. Good luck with your project; don't spend too much time and money, and you could get a real boat.
It is possible to use a mold (male or female) made from adobe to make a FRP part. To achieve a high standard the base clay mix must be plastered with lime, then burnished and sealed with soap, oil or wax. The techniques are known since antiquity, you can google "polished plaster", "tadelakt", etc.
For people like the OP hat have not spent the last 10 years mastering the traditional art of fake marble , there are alternatives if the rougher finish is acceptable. Typical techniques revolve around covering the base with something smooth and impermeable like plastic sheating or aluminum foil. For convenience sake the most widely used technique today is the brown parcel tape. Even master som in somalia (you can find him on youtube) uses it on his molds. It should stick well enough on dried earth plaster. If not, consolidating the plaster using painted on PVA or hide glue is an option.
I have not tried plastering old newspaper with PVA or hide glue over adobe, but I suspect it works just as well as on cement or lime plaster. This would allow for a little bit of sanding to smoothen the texture and can be waxed for release.
For people like the OP hat have not spent the last 10 years mastering the traditional art of fake marble , there are alternatives if the rougher finish is acceptable. Typical techniques revolve around covering the base with something smooth and impermeable like plastic sheating or aluminum foil. For convenience sake the most widely used technique today is the brown parcel tape. Even master som in somalia (you can find him on youtube) uses it on his molds. It should stick well enough on dried earth plaster. If not, consolidating the plaster using painted on PVA or hide glue is an option.
I have not tried plastering old newspaper with PVA or hide glue over adobe, but I suspect it works just as well as on cement or lime plaster. This would allow for a little bit of sanding to smoothen the texture and can be waxed for release.
Thank you Rumars for your practical observation and time. I think the polished plaster method is the best in my case, although it is the most difficult, as I have thick nylon to hold it inside the mold. However, I think it might react with the polyester layer even after applying the separation wax. What do you think? I look forward to your answer. Thank you very much.
This is the AI answer, taking into account all your ideas, guys.
unknown AI answer said:+ Wax Separator
Advantages:
Quickest and easiest solution.
Doesn't require much preparation.
Fiberglass won't stick to nylon if wax/separator is applied.
Disadvantages:
It's difficult to achieve a very smooth surface.
Wrinkles or folds may appear in the nylon, making the defect visible on the boat's surface.
This is a temporary and quick solution, but it's not professional.
---
2. Paper Mache (Paper Mache)
Inexpensive and easy to shape.
Easily correct any defects.
Is affected by humidity (must be covered with a layer of plaster or putty afterward).
Shrinks slightly after drying.
Takes a long time to fully cure.
It's useful if you're just making a prototype for testing.
---
3. Plaster
It gives you a very hard and smooth surface after sanding.
It's easy to polish and repair any defects.
It's brittle and easily breaks if the mold is large.
It's heavy.
Excellent if you want a very smooth surface (but requires experience in leveling and sanding).
---
4. Newspaper + PVA Glue (the classic method for papier-mâché)
Easy and very cheap.
Slightly stronger than paper pulp.
Unsmooth surface; requires putty or a layer of plaster to level it.
Takes a long time to dry.
Better than paste, but doesn't give immediate smoothness.
---
Since you've worked hard and want a practical result for your mold project:
If your goal is professionalism and precision, use a mixture of:
Newspaper + PVA to fill the basic shape,
Then a layer of gypsum plaster for leveling and smoothness,
Finally, a layer of spacer wax before applying the fiberglass.
My advice is to use parcel tape (the 50mm wide brown adhesive tape) to completely cover the hole you have made. Pull one boat out of it and if you want a better finish use filler and sand it smooth (like the automotive guys do) then paint it. If the boat is a success and you want to make more, use that boat to make a new fiberglass mold intended for series production.
You should read the FAO manuals on boatbuilding and look at their published designs, they are free and available in several languages.
FAO Fisheries & Aquaculture https://www.fao.org/fishery/en/vesseldesign/search
TRAINING MANUAL on the construction of FRP beach landing boats https://www.fao.org/4/al360e/al360e00.htm
30ft Fishing vessel building manual https://openknowledge.fao.org/items/f979f2ee-fa86-453c-9b43-199b18469ef5
Fishing boat construction: 4 - Building an undecked fibreglass reinforced plastic boat https://openknowledge.fao.org/server/api/core/bitstreams/e6a61972-576c-4e27-b74a-3273aee7050e/content/i1108e.htm
You should read the FAO manuals on boatbuilding and look at their published designs, they are free and available in several languages.
FAO Fisheries & Aquaculture https://www.fao.org/fishery/en/vesseldesign/search
TRAINING MANUAL on the construction of FRP beach landing boats https://www.fao.org/4/al360e/al360e00.htm
30ft Fishing vessel building manual https://openknowledge.fao.org/items/f979f2ee-fa86-453c-9b43-199b18469ef5
Fishing boat construction: 4 - Building an undecked fibreglass reinforced plastic boat https://openknowledge.fao.org/server/api/core/bitstreams/e6a61972-576c-4e27-b74a-3273aee7050e/content/i1108e.htm
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making any potentially dangerous or financial decision, always employ and consult appropriate professionals. Your circumstances or experience may be different.
When making any potentially dangerous or financial decision, always employ and consult appropriate professionals. Your circumstances or experience may be different.
Advertisement:
