Tweet
Cheers for the tips! I have seen mold making vids at carbonmods.com where they just wipe it on with a piece of cloth or tissue which seems to work ok. I was just wondering if you could get away with just loads and loads of wax instead. Sure it takes a lot of elbow grease, but its only a small boat and its less stuff I have to buy! I have use of a compressor with a paint gun of sorts - its the type with the paint pot mounted above the gun and the nozzle is about 2 inches or 50mm round with two prongs sticking out. I have no clue how to use it well though and it seems like a lot of effort with cleaning etc. I have been looking into ordering my fibreglassing supplies over here in the uk and I have found a company called ariba, although they seem to lack both tooling gelcoat and pva!
-
-
there are no chimes on the boat. the handling will suffer.Comment
-
What exactly are chines? I keep hearing about them but dont really know what they are or what they do. ThanksComment
-
They help the boat from sliding every where in the water when making turning. There are the lines that stick up out of the bottom of the hull.Comment
-
Ah yea, well I can still add them. I heard they also generate lift though as they trap air as the hull moves across across the water, I had a problem in the past with a hull jumping out the water so I figured I would leave them off. I probably will add them though, I will probably buy some triangle section balsa strips or trailing edge balsa. Any ideas where they should start/finish, how many, how big they should be?Comment
-
On most real performance boats the go from the start of the hull All the way until the hull step. If it's the boat is doubled steped then the second area will have chimes to. The best thing is to find where your ride area will be ( the part of the the hull that is touching the water when on plane) and stop the chine right before that. They need tO be in the water during a turn. Make sure they are absolutely straight though. If there not it will make the boat hook and loss control (had this happen to me on a real boat).Comment
-
No need to use pva in fact dont use it,it just gives a dull finish,i hate the stuff.Just use a good quality release wax and be sure to give it 8 or more coats before moulding.Chines are where the hull side meets the bottom ,strakes are the ones on the bottom of the hull which create lift.
MartComment
-
Yes it is a spray rail that runs along the chine which is where the side meets the bottom surface,most fast boats have whats called a hard chine(sharp edge) soft chine is where its a gradual curve.It can be quite confusing as some also call what i call strakes spray rails also lol.
Mart
Some things are explained here.
Comment
-
Well I have only block sanded the bottom/sides so the chine is as sharp or hard as it can be. I can't add a protruding spray rail like in your diagram as it would lock the plug in the mould as it would act as a negative taper angle. As for the strakes, I think I'll get some 6mm trailing edge to stick down. I'll probably do 2 per side with the inner one going from about 100mm from the stern to the bow (tapering allong the length) and then the outer one about 70mm to the bow, again, tapering. Any recommendations for good mould release wax? And infact any good fibreglass suppliers for the uk? Thanks again for the great advice as ever!Comment
-
Yes i agree you cant make it like the diagram that was just to explain what a chine rail is to those who dont know,what you need to do is make it like on my Apaches have a look at this pic and see what i mean,the angle is important to keep the boat stable at speed.The best release wax ive used and still use is Honey Wax by speciality products,you can get it on ebay or most glass supplies.By the way the easiest way to make chine rails on any boat when using wood is to make the sides overlap the bottom sheet then you can fill the area and shape it with your finger to create the slight angle or even a slight concave shape works well.
Mart
Heres the best place to get Glass supplies from i find,great to deal with and fast reliable delivery even next day if you need it fast.
Last edited by martno1fan; 07-17-2011, 07:33 AM.Comment
-
Ah, I have already planked the sides! I may get some balsa strip and shape it before sticking that on. When you say the angle is important, do you mean the angle which the spray rail makes relative to the horizontal? yours look to have around +20 degs, I guess so long as its not -x degs? Im back of holiday today so I think I am going to attempt the hatch. This part is going to take a lot of thinking in order to get it right! Hopefully I wont fall down the route of making it too small like i did last time whereby I couldn't get my hands in to work on the damn thing! I will probably put in my fibreglass order today too. I'm thinking;
Durabuild for the plug prep (expensive but perhaps worth it)
1kg tooling gelcoat
1kg White Gelcoat for the hull itself
3m^2 450gm CSM for mould making
3m^2 200gm plain woven fibreglass for the hull
1m^2 surface tissue for mould making
2.5kg lloyds approved polyester resin
A tin of honeywax for obvious reasons!
On top of this im thinking maybe some sort of polishing compound? I was wondering if something like Tcut or brasso even would work for this? I am on a tight budget and making small savings like this (as I already have these things!) helps a great deal!
Also something to mix with the resin to make it into a paste to fill out the small details where the cloth wont bend - like the strakes.
Please feel free to tell me these are all wrong! I am uncertain on cloth weights, whether I have under/over estimated cloth/resin quantitiesComment
-
Hi those items are fine,for the strakes all i use is resin and mix in some small chopped strands which cost a cpl of pounds for a kg that will last you a year or so depending on how many hulls you build,i build one a week.The spray rails can be at 0% but i find a slight angle seems to work better.For polishing the finished boat i use 3m products and if its just to give agood shine and remove any slight marks then 3m finishing material works awesome,just a lambs wool buffing wheel in your drill will work very well.Its arround 25 a ltr but works awesome and a little goes a long way.For my hulls i use a mix of csm and cloth this makes a very strong hull,i then use carbon in the engine bay areas if required.By the way a trade secret for applying your bog mix to the strakes once you have done the gelcoat is to use a silicone cake spatula these spread it in very well and the resin breaks off easy once set so the spatula is reusable.For your hull i would split a piece of your mat in half so its thinner then use that followed by a layer of cloth you might be better with a heavier cloth but for the first one try that and see what its like,you can allways add a layer later if needed then on future ones go up in weight.If you plan on using carbon then use a light cloth then carbon but still use the mat as this gives better impact strength.
MartComment
-
I meant more for polishing moulds and plugs to give a really good shine so i dont have to polish the final piece as much! Thanks for the cake spatula tip, I will just go and raid the kitchen draws...
How do you split a piece of cloth in half? I was under the impression that its better to use cloth in your actual piece as it is neater and tidier and csm for moulds cause its cheaper? I also thought it was stronger than csm if you oppose the layers at 45 degrees? I also also thought that the lower weights were better for smaller parts, like this. A lot of things I thought I knew, lol.
I was hoping to keep the weaves very tidy and neat which was why I was going to steer clear of csm for the actual hull
I dont think I am going to have the time or money to progress onto carbon fibre unfortunately, its just so expensive!Comment
-
Yes you can use it to polish the moulds prior to waxing,the mould is gelcoat same as the boat hehe.Yes cloth is tidier which is why i do the csm first then cloth on top.
A mix of csm and cloth is the best of both worlds.
You cant split cloth in half which is why i said split the mat lol
You are correct though lighter weight cloths are best suited to smaller projects,i was forgetting yours isnt a large hull sory,smallest hull i have is 120cm which is a work in progress.If you go with plain weave cloth then yes do two layers at 45% to each other or why not simply buy twill cloth which is allready made like this and doesnt cost much more just a thought.If your buying from Martin at east coast have a word about layups and he will be happy to help you decide whats best for your project.
MartComment
Comment