Loc 4-29 Ss
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PGerringer
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Yo Klint... you can find tons of glassing instructions by Dr. Glass (CTULANKO) in the Techniques forum. Check em out, you wont be disappointed.
PGerringer
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Dr. Glass will tell you to sand, sand, sand... 
Dr. Glass is gonna love that you asked that question.
Dr. Glass is gonna love that you asked that question.
A
Austin
If you want to fiberglass the fins for your LOC, which are plywood, I would reccomend you glass the ENTIRE fin, as I did on my LOC Nomad. Run the cloth from 1" past the outside edge of one fin, down that fin, across the body tube and up past the other fin an inch or so. Also extend the cloth forward past the joint about and inch or so and let it overhang past the rear of the body tube. Use Finishing resin, as it takes a while to set, soaks into the wood very well and sands much easier than regular epoxy. When all 3 fin areas are done, sand the extra cloth off the fin edges and blend the leading and trailing edge. Use another coat of resin once they are glassed if you are worried about sanding through the cloth, which would be a bad thing.
You can use primer to fill in the weave and sand the body tube overhang to blend it into the body so you get a smooth transition from glassed area to body tube. Some epoxy resin at this joint/seam where the cloth ends and the upper body tube begins will give you a little more freedom in blending.
Cya
You can use primer to fill in the weave and sand the body tube overhang to blend it into the body so you get a smooth transition from glassed area to body tube. Some epoxy resin at this joint/seam where the cloth ends and the upper body tube begins will give you a little more freedom in blending.
Cya
kgholloway
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Dr. Glass,
Your last post was very informative in regards to the Loc 4-29SS fiberglassing that you'd recommend. I'm just getting into fiberglassing and wondered if you would explain something for me. From what I've seen there are three methods of applying fiberglass in common use.
The first one is what you just described, laying one or more layers of fiberglass cloth across the fins and the body tube between them and then applying resin. The airframe tubing ahead of the fins may optionally be glassed.
The second also lays the fiberglass across the fins but the body tube, and possibly the fins, have at least one prior layer of fiberglass.
The third method applies one or more layers of fiberglass to both the body tube and the fins. The tube and fins are then "cleaned up" and assembled in the normal manner with epoxy filets at the joints.
Which of these methods do you consider the easiest to master? Which would be the strongest? Would you recommend any specific method based upon the design of the rocket, the weight of the rocket, or the size (diameter) of the airframe?
Ken Holloway, NAR #78336, L-1
Your last post was very informative in regards to the Loc 4-29SS fiberglassing that you'd recommend. I'm just getting into fiberglassing and wondered if you would explain something for me. From what I've seen there are three methods of applying fiberglass in common use.
The first one is what you just described, laying one or more layers of fiberglass cloth across the fins and the body tube between them and then applying resin. The airframe tubing ahead of the fins may optionally be glassed.
The second also lays the fiberglass across the fins but the body tube, and possibly the fins, have at least one prior layer of fiberglass.
The third method applies one or more layers of fiberglass to both the body tube and the fins. The tube and fins are then "cleaned up" and assembled in the normal manner with epoxy filets at the joints.
Which of these methods do you consider the easiest to master? Which would be the strongest? Would you recommend any specific method based upon the design of the rocket, the weight of the rocket, or the size (diameter) of the airframe?
Ken Holloway, NAR #78336, L-1
A
Austin
Ken,
The methods you described are pretty much right on as far as different techniques. Regarding which to use, it would depend on the materials involved.
When glassing raw wood to paper, phenolic or Quantum tube, I would normally use the first method. Reasoning for this is two fold; you get a better bond when glassing raw materials all together than with a previously glassed surface, since the resin can "soak" in to the materials and bond every corner. Also, you eliminate overlapped cloth, which would occur in your second method.
The second method usually works well too, as long as the pre-glassed surfaces are scuffed up enough to hold the resin of another layer of cloth. This seems to be used more when G10 Fiberglass fins are used in conjunction with paper, phenolic or Quantum body tubes. With G10 fins, I usually only glass about the first two inches or so up the side of the fins, unless they have a shorter span, in which case I encase the entire fin in cloth/resin.
Another scenario though would be the use of wood or G10 fins with a G12 fiberglass body tube. In this case I would follow the method you described as the third case, applying fillets only, but, I would probably glass the fins inside to the motor mount and inner wall. Speaking of your third method and another question you posed, some people glass their body tubes prior to construction as it is easier to do on a clean tube then fight trying to get around it with fins in the way. My L3 project is like this, using pre-glassed tubing and installing G10 fins. For my peace of mind, I will still add a layer of cloth to the outside and inside joints for insurance. You can never build too strong when it comes to HPR!
As far as which is the strongest, I would think the glassed tubing with fins glassed to it outside and in all at once would be the strongest method of attachment. Also note that, depending on the materials and motor range of the model, I will use different thicknesses of cloth. I have used 1/2-3/4 oz on midrange kits like Launch Pad and others that have surface mount balsa and basswood fins; it added a layer of strength and has since stood up to alot of abuse and at the same time the light cloth helped keep the weight down. 1 1/2-2 oz cloth has been used on L1 and L2 birds and I use 6oz cloth on large L2 and L3 ships. One wrap around a body tube has done the trick for me; I hear alot about guys using extremely large cloth with multiple wraps, which IMHO would only apply to high stress or mach+ models. For the sport HPR flier, a single wrap will do just fine.
The biggest trick is to get the tube to hold the cloth. If it's a paper tube, I peel away the glassine layer so raw paper tubing is exposed. It really sops up the glassing resin and nearly turns the tube into steel! Just last week I had a Thoy Phoenix come in without parachute after the shock cord snapped at ejection; it was completely glassed and landed forward tube first without a scratch! Fiberglassing the whole model made it very strong where I know the stock paper tube would have needed to be replaced.
On G12, Quantum or Phenolic tubes and G10 fins, I use at least 80 grit paper or lower to really cut some good grooves into the surfaces. This gives a good gripping surface for the glassing. You can glass Quantum tubes, but I limit this to the lower fin area/canards only. Glassing an entire QT would restrict it's ability to expand and contract with temperature changes and could cause damage to the tube or problems with the piston ejection. However, since I fly in Mid-Ohio during the below freezing months and own several PMl Quantum kits, adding glass cloth to the lower fin area has helped prevent the shattering effect that has occured with non-glassed Quantum tubes.
As far as which is easiest to do, I would think G12 or pre-glassed body tube with G10 fins and fillets only is the easiest. Actually doing the glass work is about the same no matter which method you use. Also, you can apply fiberglass cloth using one of two methods. The cloth can be layed over the surface and resin can be applied and pressed through the cloth but this method only works well when using Finishing Resin, which is thinner and I recommend using it when dealing with wood surfaces. The other technique, and the one I use, is to apply the resin to the surfaces, then lay the cloth on and squeegy the excess out. The cloth stays in place easier when layed over a resined area. Also, this method allows the entire surface to become soaked in resin, and as you squeegy the cloth, the excess resin pushes up through the weave and off to the the sides insuring both the cloth and surface are well soaked.
For the most part, I use 30 min epoxy and 2oz cloth for my L1 and most L2 rockets. It's applied over G10 fins ( I rarely use ply, just because I like G10 better...but everyone has their preference and either work well). Additionally, I will use the combination in your first method the most; glassing over G10 fins and Quantum tube or over Ply fins and paper tube. I have had an occasion to glass over G12 tubing, which would fall more in the method 2 category, but I rarely just glue fins together without glassing due to my location and it has helped keep many HPR models in my fleet in top shape.
It was a bit long winded, but I hope I answered most of your questions.
Have a great day!
Carl
The methods you described are pretty much right on as far as different techniques. Regarding which to use, it would depend on the materials involved.
When glassing raw wood to paper, phenolic or Quantum tube, I would normally use the first method. Reasoning for this is two fold; you get a better bond when glassing raw materials all together than with a previously glassed surface, since the resin can "soak" in to the materials and bond every corner. Also, you eliminate overlapped cloth, which would occur in your second method.
The second method usually works well too, as long as the pre-glassed surfaces are scuffed up enough to hold the resin of another layer of cloth. This seems to be used more when G10 Fiberglass fins are used in conjunction with paper, phenolic or Quantum body tubes. With G10 fins, I usually only glass about the first two inches or so up the side of the fins, unless they have a shorter span, in which case I encase the entire fin in cloth/resin.
Another scenario though would be the use of wood or G10 fins with a G12 fiberglass body tube. In this case I would follow the method you described as the third case, applying fillets only, but, I would probably glass the fins inside to the motor mount and inner wall. Speaking of your third method and another question you posed, some people glass their body tubes prior to construction as it is easier to do on a clean tube then fight trying to get around it with fins in the way. My L3 project is like this, using pre-glassed tubing and installing G10 fins. For my peace of mind, I will still add a layer of cloth to the outside and inside joints for insurance. You can never build too strong when it comes to HPR!
As far as which is the strongest, I would think the glassed tubing with fins glassed to it outside and in all at once would be the strongest method of attachment. Also note that, depending on the materials and motor range of the model, I will use different thicknesses of cloth. I have used 1/2-3/4 oz on midrange kits like Launch Pad and others that have surface mount balsa and basswood fins; it added a layer of strength and has since stood up to alot of abuse and at the same time the light cloth helped keep the weight down. 1 1/2-2 oz cloth has been used on L1 and L2 birds and I use 6oz cloth on large L2 and L3 ships. One wrap around a body tube has done the trick for me; I hear alot about guys using extremely large cloth with multiple wraps, which IMHO would only apply to high stress or mach+ models. For the sport HPR flier, a single wrap will do just fine.
The biggest trick is to get the tube to hold the cloth. If it's a paper tube, I peel away the glassine layer so raw paper tubing is exposed. It really sops up the glassing resin and nearly turns the tube into steel! Just last week I had a Thoy Phoenix come in without parachute after the shock cord snapped at ejection; it was completely glassed and landed forward tube first without a scratch! Fiberglassing the whole model made it very strong where I know the stock paper tube would have needed to be replaced.
On G12, Quantum or Phenolic tubes and G10 fins, I use at least 80 grit paper or lower to really cut some good grooves into the surfaces. This gives a good gripping surface for the glassing. You can glass Quantum tubes, but I limit this to the lower fin area/canards only. Glassing an entire QT would restrict it's ability to expand and contract with temperature changes and could cause damage to the tube or problems with the piston ejection. However, since I fly in Mid-Ohio during the below freezing months and own several PMl Quantum kits, adding glass cloth to the lower fin area has helped prevent the shattering effect that has occured with non-glassed Quantum tubes.
As far as which is easiest to do, I would think G12 or pre-glassed body tube with G10 fins and fillets only is the easiest. Actually doing the glass work is about the same no matter which method you use. Also, you can apply fiberglass cloth using one of two methods. The cloth can be layed over the surface and resin can be applied and pressed through the cloth but this method only works well when using Finishing Resin, which is thinner and I recommend using it when dealing with wood surfaces. The other technique, and the one I use, is to apply the resin to the surfaces, then lay the cloth on and squeegy the excess out. The cloth stays in place easier when layed over a resined area. Also, this method allows the entire surface to become soaked in resin, and as you squeegy the cloth, the excess resin pushes up through the weave and off to the the sides insuring both the cloth and surface are well soaked.
For the most part, I use 30 min epoxy and 2oz cloth for my L1 and most L2 rockets. It's applied over G10 fins ( I rarely use ply, just because I like G10 better...but everyone has their preference and either work well). Additionally, I will use the combination in your first method the most; glassing over G10 fins and Quantum tube or over Ply fins and paper tube. I have had an occasion to glass over G12 tubing, which would fall more in the method 2 category, but I rarely just glue fins together without glassing due to my location and it has helped keep many HPR models in my fleet in top shape.
It was a bit long winded, but I hope I answered most of your questions.
Have a great day!
Carl
kgholloway
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Carl,
Thanks for the help. Your explanations really cleared up a lot of questions I had regarding fiberglassing rockets.
Hope to see, and thank, you personally at one of the Goraj launches this season.
Ken Holloway, NAR #78336, L-1
Thanks for the help. Your explanations really cleared up a lot of questions I had regarding fiberglassing rockets.
Hope to see, and thank, you personally at one of the Goraj launches this season.
Ken Holloway, NAR #78336, L-1
A
Austin
Ken,
I just noticed you are in NE Ohio...small world! Actually I am originally from Warren, up near your neck of the woods. I will look forward to seeing you at a Goraj launch...it was a fantastic time last Saturday! Look me up; I'll be the guy with two kids, alot of low and mid HPR and my PML Amraam 4 flying on serious "J" power.
Good luck on the Glassing and keep asking questions...that's how I have learned over the years; We'll try to help anytime if we can!
Cya,
Carl
I just noticed you are in NE Ohio...small world! Actually I am originally from Warren, up near your neck of the woods. I will look forward to seeing you at a Goraj launch...it was a fantastic time last Saturday! Look me up; I'll be the guy with two kids, alot of low and mid HPR and my PML Amraam 4 flying on serious "J" power.
Good luck on the Glassing and keep asking questions...that's how I have learned over the years; We'll try to help anytime if we can!
Cya,
Carl
