<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by KANDU
<u>Question:</u> I’m wondering what the consensus of opinion is on male vs. female molds?
i.e. which is easier, problems, weight issues etc…
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The rule of thumb that I have followed (a personal decision) is that “Male Plugs” vs. “Female Molds” was one of quantity of boats to be built?
Consider that either one requires a lot of sanding a fairing before the hull is done. Here are my thoughts:
MALE PLUG METHOD: Used for one-off boats. Work to finish hull will be done on exterior of the hull while it is still on the male plug. The male plug doesn’t have to finished as well as a female, as that surface will be “inside” your hull. It still has to be fair and still needs a parting agent though.
FEMALE MOLD: More work up front. Requires an excellent finish to a male plug - from which you make a female mold. All work is still done on the male plug. You then make a multilayer mold (over the top of the male plug) and when removed this becomes your female mold. The inside of the female mold will be reflected on the outside of your finished hull. It has to be smooth, polished and free of any dust, dirt, etc. This mold can then be used to make more than 1 hull, saving you finishing time. This means that (usually) when you pull the hull from inside a female mold, the hull exterior should need very little finishing. The problem I have found is getting the cloth to sit down and stay in the tight and usually very thin bow portion of the hull mold. If you are laying up a hull with a flat stem at the bow (for eventual bumper) it is a little easier. But the process is definitely more for multiple hulls from same mold.
Again, from personal view, if I do a hull off a male mold, and like performance, style, look, etc. I can always use the prototype to make a female mold later. If you are doing prototype work with possible hull modifications, you waste a lot of time building a female mold for only 1 use. In fact, I prefer the foam core/plug method, where foam is shaped, then glassed and the design tested. If no good, you have invested in very little time and very few materials. If it works - use if to build a mold to make hulls for friends or profit. If it doesn’t work, dump it and start over. Or, hack off the stern add some new foam, shape and glass and try again. Very easy, very inexpensive, no way near the time expending gluing up and fairing individual strips of wood.
Simply look at the big boat world and take cues from them. One-off boats can/are strip built with wood, cold molded using veneer, (time consuming) while boats that will have a lot of hulls made will go through the expense of making a mold, and recover cost in volume of sales.
For little boat of the r/c variety, the same is true… if you make a mold and only a few boats are sold, costs will be high in order to recoup the cost of the mold. As volumes go up, costs come down. It is a mfg. gamble whether they will sell - so initial boats may also be more expensive - or they can be really cheap if costs are low initially to get buyers.
Microsail doesn’t sell a lot of F3 foilers, but has the same tooling costs (on average per hull) as does Peter at Climate Boat Works with his Epoch tooling. I’m not going to debate the subject here - but if you only sell 4 boats, it has to impact the overall cost and profit of your sales, compared to the sale of 50- 100 or more.
Now, if we all had access to CNC milling and could turn computer designs into milled plugs, certainly it might make a difference.
I guess in the end - if a personal design/prototype, I would use male plug method. If a proven design, and you think you will make more than one hull, use the female mold.
I’m sure others will comment and have their opinions that may differ. These are mine.