Styroplast #024

Styroplast #024
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SKU: 024-QT
Weight: 3.50 lbs
Fortifier/additive: Not an additive
Feel: Smooth Plastic
Application time: 10-20 Minutes
Work time: 30-45 minutes
Cure time: 12 hours
Weatherproof: Weather Resistant
Sandable: Sandable only before completely set
Paint/Stain: Second coat or paint MUST be applied within 2-12 hours or will not stick
Compatible with: Can be applied over any other coating; Grit can be used on top as texture

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Whether you are producing signage or protecting delicate forms for themed scenery, Styroplast will outperform all other coatings. Our one-of-a-kind brush-on encapsulant has a fast set time and clings well to vertical surfaces. It is designed to provide an impact and fire resistant shell for numerous substrates including EPS/Styrofoam, insulative foams, and wood. Our formula is extra thick, as it especially formulated to be the best brush on foam encapsulent. Spray application is not recommended. Very little weight is added to the foam structure reducing the need for structural support. Water resistant and chemically inert once cured, it is human- and animal-safe. Superior hardness, fast cycle time, easy to apply, lightweight and short cure time. Environmentally safe once cured. Superior hardness and greater moisture resistance than epoxies.

Coverage: This coating is very strong, even when applied very thin:

1/64 inch thick
1/32 inch thick
1/16 inch thick
1/8 inch thick
1/4 inch thick
Quart Coverage:
26 sq ft
13 sq ft
6 sq ft
3 sq ft
1.5 sq ft
Gallon Coverage:
103 sq ft
51 sq ft
26 sq ft
13 sq ft
6.5 sq ft


Simple Brush-On Application Tips: Mix With Part B Warm. Mix EXACT proportions. (See Mixing, below.) Apply in Cool Dry Area. Dry in Warm Humid Area.
Apply multiple coats when needed. Best to apply 2-12 hours after each coat is applied.  Easily sanded between coats. Use our Medium Mesh for extra strength, especially in seams and corners. 

Material PreparationApplication in humid conditions may create gas bubbles that rise to the surface during drying. Thoroughly power mix Poly component before beginning to apply. In large quantities, usually this takes a minimum of 5 minutes per 1 gallon pail with proper mixing equipment. Mix with a slow speed drill and paddle mixer. Hand mixing is fine for small quantities.We highly recommend using our accessory Syringe for small batches (see the Related Products link at the bottom of the page). An air conditioned room will deliver an ideal low humidity and slow drying environment. Move coated object to a warm area to promote faster drying. Warming Part B to 70-75 degrees before use will make mixing much easier.

EquipmentOrdinary paintbrush, notched trowel (preferred), or squeegee. Clean up (before mixture dries) with acetone or MEK.

ReactivityPotlife (brush): 15 minutes @ 76°F (Up to 30 minutes in cool dry environment); Potlife (trowel):12 minutes @ 76°F (Up to 20 minutes in cool dry environment.)

Cure TimeApplied coating will set in about 2 to 5 hours at 70°F, depending on film thickness, liquid material temperature and the substrate temperature. Generally complete cure takes from four to five days at room temperature. Product can be placed into service after one complete day of cure at 70°F minimum. After four days cure the hardness is around 65 shore D . Higher hardness may be attained by post heating the part to 90 – 110 F after 6 hours cure time. Prime or paint the plastic coated part the next day, or better, later the same day. If you paint after 12 hours you will need to lightly sand the surface, or better to apply an epoxy primer for paint to stick.

Mixing: 1 unit ISO: 3 units POLY by volume or 1 unit ISO: 3.55 units POLY by weight. Must be very exact proportions. Highly recommend using our reusable accessory measuring Syringe or an accurate scale for small quantities. Neutral (tan). Paint within 12 hours or use epoxy primer for best bond. Or just lightly sand after 12 hours for good adhesion.

Fire Resistance: Styropalst is self-certified as UL-94 V0 at 60 mils thickness. Flash PointASTM D-56 (TCC): Greater than 200°F

Chemical Resistance: Hydrolytic Stability: Recovers after 10 days 150°F immersion. Generally resistant to most dilute aqueous agents when cleaned off within 10 hours of contact. Very difficult to stain by virtue of its high hardness and low porosity. Constant or frequent immersion service not recommended.

Tensile Properties: ASTM D-412; Tensile Strength: 2742 psi; Elongation: 9.7 %; Yield Strength: 2653 psi; Elastic Modulus: 17,127 psi.

Tear Resistance: ASTM D-624: 156 lb/in.

Hardness: ASTM D-2240; Shore D: 65 - 70 depending upon post cure Conditions.

Liquid Component Properties: Solids: % Nonvolatile (wt): 100% Viscosity: Poly Component: Moderate - High @ 77°F; ISO Component: 200 cps @ 77°

Density: Poly Component: 12.11 lbs/gal. ISO Component: 10.3 lbs/gal

Toxicity: ISO Component contains isocyanate (the ISO side has similar health hazards as Gorilla glue). Due to toxicity, spraying is not recommended. When brushing, ventilation, gloves and protective clothing required during application.

Shelf Life: The shelf is twelve months for Part B and six months for Part A. They will last longer than that when stored properly. The ISO, when left open, will draw moisture out of the humid air and create bubbles, so keep container closed at all times.

WARRANTY: HWFF Inc./dba Hot Wire Foam Factory warrants this product to be of merchantable quality when used or applied in accordance with the instructions herein. The product is not warranted as suitable for any purpose or use other than the general purpose for which it is intended. Liability under this warranty is limited to the replacement of its product (as purchased) found to be defective, or at the shipping companies’ option, to refund the purchase price. In the event of a claim under this warranty, notice must be given to The Hot Wire Foam Factory in writing. This limited warranty is issued and accepted in lieu of all other express warranties and expressly excludes liability for consequential damages. MSDS available.

What do I need to waterproof and hard coat styrofoam making a styrofoam pontoon for kayak?

Hi Tony,
Styroplast will be the best.
It's a very strong waterproof encapsulating coating that is very lightweight in proportion to its impact resistance. You might consider adding Mesh where there are seams and at any stress points.
Would love to see how this turns out,.

Will Styroplast also stick to wood?

It will stick to wood, but if the wood is sealed or painted it won't stick as well as if it is still somewhat porous.


If work time is 20 minutes, what quantity of mixed SP does that represent? I don't want to mix an entire gallon can of the coating and then have half of it harden while I am trying to spread the first part. I am working in a fairly warm building too, so I have to factor that in. What quantity do you recommend i mix each batch?

I'd say watch the video on the Styroplast page to get a good feel on how much you can work with per mix. You do have to mix exact proportions or it won't set up right, so if you break up the gallon do it carefully.

It will set up faster if the weather is warm and humid. It's best to get the Part B (white) warmed up to at least 75 degrees so it is more liquidy when you mix it. Then apply it in a cool place, preferably cooled with an air conditioner which will dehumidify the air (NOT a swamp cooler).

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3 Most useful customer reviews
Janet Gernand
May 22, 2017
This customer purchased the item at our site.
I love this product! I design and build sets for school plays and it's a "must have" product to keep on hand that makes foam pieces more sturdy and longer lasting.
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Rhonda Jenkins
Sep 18, 2015
Styroplast is great for protecting foam! I love the ease of using and how fast it dries and cures!
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Tyler Wilson
Jan 1, 1991
This customer purchased the item at our site.
EVA foam for our Cosplay props and costumes is our bread and butter right now. We've been coating it with Styroplast. I ran into one girl not to long ago that uses worbla. I pitched Styroplast to her and she complained it was too heavy. If you don't know what that is, worbla is a thermoplastic with a very low melting point. It is outrageously expensive. A two-square-foot sheet goes for about 30 bucks. That's why Styroplast is a better alternative.
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