First thing I want to say here … Attempting this on a < 2mm thick edge is probably not worth the trouble ’cause its not gonna last beyond the first bump on the sand or hull. Below IS good to restore a nice perimeter on an older paddle or to fill in some jagged spots on those < 2mm paddles as best one can. The following tips can also be applyed to touching up that banged up rudder blade as well. Paddle and ( rudder ) “blade” interchangable here. More below on this.
What to do:
Mask area to be built up 1/4″ inch back from edge on both sides of the blade. Any big chips or dings you want to fill get the same 1/4″ tape ‘fence’ put around them. If a missing chunk is ragged, sand/file edges smooth and bevel it a bit on both sides for more mechanical grip. Try to keep as much original paddle land as possible here always.
Sand to 1/4″ tape line for prep. Do both sides of paddle at this time. A tiny bevel will provide more surface to bond to but only do this deeper than token at the damaged areas … 100 – 120 Grit is good for this stuff. No rougher. Less and you give up a little mechanical key.
Pull masking tape and retape w/ fresh again at 1/4″ line. Please use best quality tape now. Also place another layer of tape over this one at 1/8″ or half the distance of first one to edge … Do above 1/4″ & 1/8″ on one side of the paddle only …
Mask the ‘backside’ (opposite side of what you are going to work on ) of the paddle blade right to the very edge.
Next mask ‘backside’ of repair to over hang 1/4″ max away from edge … Creating a dam so to speak. try to do this initial extension in one shot with no breaks in the tape for best results … After that see below. Note here … If you are considering modifying the original shape to something else, say beyond the 1/4″, now is the time to make your dam larger if desired. That said, please heed the following rule of thumb, the max extension you can hope to ever have stay on is LESS than the thickness you are bonding to. If you want it larger, you gotta glass it to the beveled blade SURFACES … A separate article for a rainy day.
Follow up with as many plys of tape as you want but use enough that the shape won’t change / sag / curl as you start working it. That first perfect ply on the paddle backside will help keep resin from wicking under the dam tape as you poke and prod it. A trick to speed things up here is instead of trying to tape perfectly every ply after that first one is to just rip and place little ones all over to make the whole dam isotropic and then cut a clean perimeter edge with scissors when thickness is good. Tweak to straight by bending if necessary but beware of springback / tape creep as you work.
Important ! Make sure the dam comes STRAIGHT OUT from edge as it goes around the paddle perimeter and does not curve/hook towards or away from area being built up by new material. This is one reason to not have tape come out more than 1/4″ or so from edge. No worries on straight runs but doing the curved tips will cause tape to want to curl. Again, use more (pieces) tape if you want to but do more than 1/4″ beyond or so … Really press the tape down around any chips or chunks you are trying to fill in too ’cause resin is going to try to wick under it. If chunk is ragged, sand edges smooth and even bevel it a bit on both sides for more mechanical grip.
A smart thing to do with tape in hand here is to mask w/ paper the rest of paddle now. Shaft too ’cause you neva know what you touch sometimes with gloves on. If its covered, you don’t have to worry.
You have some choices to make now.
At this point you could use just about anything from bondo to vacuumed down, cut-on-the-bias glass, carbon etc. to do the perimeter. Some choices below.
* Low density filler … Light, EZ to work and will protect the edge in a ablative sort of way.
* High density fillers ( including chopped strand ) … Heavier, but more resistant and will wear better + most likely bond better too.
Note on the above fillers, its possible to simply tape both sides of the blade sans dam and fill everything on both sides in one shot. More sanding, less taping. If I was using the fillers, I would tape both sides and carefully squeegee both sides in one shot. Pull the tape and razor blade right to blade faces before hardening … Let harden and go right to final sanding grit. Notes for rudders, Unless the blade is seriously delamed or broken, filler is probably enough to hold everything together. A little less work + fairing too. While blade is out, might as well check out the shaft. blade and rudder tube on the boat for any cracking or unbonding inside too.
* Use long strands of Uni carbon or glass. Forget kevlar, not worth the trouble IMHO. Note; to make your own uni, buy some cloth which is more useful for other projects and just pull a few long bundles out of it, viola ! Uni. The uni works pretty good here to make an even perimeter but is more prone to getting knocked and peeled right off unless its got a little more surface to grab such as on a thicker wood blade … as does everything else.
* Lightweight glass or carbon ( <4oz ) cut continuously to shape and laid on, on the bias. Strong, resistant + good bond. Not as prone to ‘peeling’ off. Realistically, this could turn into almost as above uni but if you keep the glass @ 45 / 45, its pretty trick. Carbon is harder just because you cannot see if its contacting the blade edge, you just have to ‘know’ it is … I know you glass guys understand what I mean here … Can’t be taught. This last one is getting a little crazy and its ideal if you can get some pressure on everything too. See below.
*** Another one ! I will talk about after procedures for above materials.
Material Decided on, what to do with each:
* Fillers : If not doing the one shot thing >>> Mix up and squeegee in nice and neat. then skip to: ” Once it is not so juicy… but resin still wet,” below.
* Glass / Carbon Uni : Wet out with Epoxy on a flat surface, squeegee out excess resin and lay onto sanded-taped-masked-horizontally sitting blade. If you have to, place, PROTECTIVELY WRAPPED shaft LIGHTLY in a vice to achieve best compromise of levelness. Do NOT crank down on the vice ! Mo’ betta to just use a simple spring clamp. Do not use too much resin in the first place. Place wet out, long strands onto blade edge / dam / jagged spots & poke into position to just along the 1/8″ tape line and hanging off the edge to level with original paddle perimeter and surrounding surface levels (or however you want to modify it ) OR just over that. Please read below “smooth out” step to understand everything and help decide based on your skill level how much you want to leave “just over” : ) I.E. if you want to sand more than necessary, go higher than surrounding surface areas. Patience and time spent here filling only as needed are rewarded.
* Bias Cut Glass / carbon : Wet out paddle and drop on dry, cut with sharp scissors, material down, wet out with light tamping of brush. Add plys to just level or just over as above.
Gently work out all air and as much resin as possible while still keeping ALL fiber strands in place WITH THE 1/8″ TAPE LINE JUST SHOWING.
Once you get excess resin worked out ( uni ) or fabric wet out ( glass / carbon on bias ), move any errant strands off the line ( back towards paddle edge ) and pull 1/8″ tape up. Revealing the original 1/4″ ‘fence’ ply of tape.
Once it is not so juicy … but resin still wet.
Smooth out strands that might have flopped back over the tape line and excess resin towards edge once again if necessary. Then lay some PRECUT, WRINKLE FREE, clear, 4 mil plastic down over strands/filler starting at the original 1/4″ tape line and moving outward towards paddle edge with a tiny squeegee. You should have a tiny bit of resin/filler ‘backfill’ to the 1/4″ tape line but fiber strands stay in place at 1/8″. Peel ply will work here too but if you get the plastic right, there is little to no work left. Plastic works better for fillers here BTW.
Depending on your personality … Walk away or stand and babysit now. Either way …
… Let cure before pulling plastic / peel ply.
Pull all tape including backside. If you got your tape dam nice and straight from the beginning you can simply lightly sand the ‘backside'(other side of blade ) of this newly filled dam area for prep and to knock down any excess resin that may have migrated under the tape if need be. Use this new material and proceed as above ( minus the need for a new tape dam ) to do the other side of the blade. If the dam is high or low ( remember me stating to do it straight out ? ), you gotta do some sanding to correct things by doing above over on the same side then back side or simply living with the initial step’s level of competency and proceeding to the other side. Please remember part of the title was ” And have it come out nice : )
IF DONE RIGHT : ) the only sanding ness on blade is a tiny bit from the thickness of the 1/4″ tape line….. a good reason to use the best 3M Pinstripe tape + it will do the curves of the blades in a single piece and is real thin. Use a tiny ( < 1 sq. in. ) sanding block and you should be able to START with 1000 grit to fair perfectly with original paddle and then 1200 + grit to buff to as new.
Even this little line unsanded / faired line as is will probably be better than the jagged edge like before. You may consider adding some pigment to resin for a colored edge look.
Side note to above … If you are really feeling good, your initial tape line / layers can be 1/8″ and 1/8″ with an initial prep sand to only 1/8″ instead of 1/4″ and 1/8″. This yields an even smaller line … In fact, you can be gutsy and simply simply sand to 1/8″ tape to 1/8″ and then pull the tape and ‘flatten’ the resin down to flush. This will come out smooth but usually results in resin smearing around uncontrollably and regrettably. Mo’ betta to use the tape, get a perfect line and simply start with 1000 grip and a tiny sanding block.
Wood guys … Beware if you use carbon for this as the carbon when sanded next to open wood will ‘dirty’ the grain black and never really comes out without excessive sanding. Glass will stay ‘clear’.
Shape ‘new land’ on outside edge of paddle to original or to taste … Should be plenty there to file first followed up with 320/600 wet or dry. on the edge.
*** THEE OTHER ( and best ) ONE … Skip the dam step, otherwise tape both sides as above and glass / carbon BOTH sides in one shot by applying resin, letting it tack and placing glass / carbon on both beveled edge sides in one shot … You can do this with separate pieces per side or simply ( AND WAY MORE DURABLE ) wrap the glass / carbon AROUND the edge … The tacked up epoxy, working like contact cement, will ‘grab’ the glass / carbon and hold it bent around that tight radius … Let it sit for 10 – 15 minutes in place there before wetting out as normal. Let this ply ‘kick in’ as the first one and continue to build up as thick as you desire but remembering above rule of thumb about thickness : bond area. Time it right and you can simply and perfectly, slice through all the overlapped plys right to the very paddle surface and tape line with a utility blade. Wet sand as is or sand and apply a layer of neat resin as above tape / plastic method. Notes here … This way sounds fast but you gotta be good or else its MORE work and will come out horribly.
Use in best of health and happiness.
a hui hou,
pat
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